From all eternity, God has called man to participate in the life of the Blessed Trinity.“This vocation to eternal life is supernatural " (Catechism, 1998).  To lead us to this supernatural final end, God grants us even here on earth a beginning of this participation which will reach its fullness in heaven and which St. Thomas Aquinas calls “a foretaste of glory."  This gift is sanctifying grace :
• it “is the gratuitous gift that God makes to us of his own life, infused by the Holy Spirit into our soul to heal it of sin and to sanctify it" (Catechism, 1999);
• “it is a participation in the life of God" (Catechism, 1997; see 2 Pet 1:4), who divinizes us (see Catechism, 1999);
• it is, therefore, a new, supernatural life; a new birth through which we are made children of God by adoption, sharers in the natural filiation of the Son: “sons in the Son"; 
• it thus introduces us into the intimacy of the Trinitarian life. As adopted children we can call God “Father," united to his only Son (see Catechism, 1997);
• it is the “grace of Christ," because in our present situation—that is, after sin and the Redemption worked by Christ—grace reaches us as a participation in the grace Christ won for us (Catechism, 1997): And from his fullness have we all received, grace upon grace (Jn 1:16). Grace configures us to Christ (see Rom 8:29);
• it is the “grace of the Holy Spirit," because it is infused in the soul by the Holy Spirit. 
Sanctifying grace is also called habitual grace because it is a stable disposition which perfects the soul through the infusion of virtues, to enable it to live with God, to act by his love (see Catechism, 2000). 
The first action of grace within us is justification (see Catechism, 1989). Justification is the passing from the state of sin to the state of grace (or “of justice," because grace makes us “just").  This takes place in Baptism, and every time that God pardons our mortal sins and infuses sanctifying grace (ordinarily in the sacrament of Penance).  Justification “is the most excellent work of God's love" (Catechism, 1994; see Eph 2:4–5).
God does not deny his grace to anyone, because he wants everyone to be saved (1 Tim 2:4): all are called to holiness (see Mt 5:48).  Grace “is in us the source of the work of sanctification" ( Catechism, 1999); it heals and elevates our nature, wounded by original sin, and makes us capable of acting as God's children,  and of reproducing the image of Christ (see Rom 8:29): that is to say, of being, each one, alter Christus, another Christ. This resemblance to Christ is manifested in the virtues.
Sanctification means growing in holiness, attaining an ever more intimate union with God (see Catechism, 2014), to the point of becoming not just another Christ but ipse Christus, Christ himself  —one and the same with Christ, as a member in his Body (see 1 Cor 12:27). To grow in sanctity requires freely cooperating with grace, and this entails effort, struggle, because of the disorder introduced by sin (the fomes peccati, the inclination to sin). “There is no holiness without renunciation and spiritual battle" (Catechism, 2015). 
Therefore, in order to conquer in the ascetical struggle, we need to ask God for grace through prayer and mortification (“the prayer of the senses"),  and receive grace through the sacraments. 
Our union with Christ will be definitive only in heaven. We have to ask God for the grace of final perseverance, that is, the gift of dying in God's grace (see Catechism, 2016 and 2849).
4. The theological virtues
In general terms, virtue “is an habitual and firm disposition to do the good" ( Catechism, 1803).  “The theological virtues relate directly to God. They dispose Christians to live in a relationship with the Holy Trinity" (Catechism, 1812). “They are infused by God into the souls of the faithful to make them capable of acting as his children" (Catechism, 1813).  There are three theological virtues: faith, hope and charity (see 1 Cor 13:13).
Faith “is the theological virtue by which we believe in God and believe all that he has said and revealed to us, and that Holy Church proposes for our belief" (Catechism, 1814). By faith “man freely commits his entire self to God,"  and strives to know and do the will of God: The righteous shall live by faith (Rom 1:17). 
“The disciple of Christ must not only keep the faith and live it, but also profess it, confidently bear witness to it, and spread it" (Catechism, 1816; see Mt 10:32-33).
Hope “is the theological virtue by which we desire the kingdom of heaven and eternal life as our happiness, placing our trust in Christ's promises and relying not on our own strength, but on the help of the grace of the Holy Spirit" (Catechism, 1817).  Charity “is the theological virtue by which we love God above all things for his own sake, and our neighbor as ourselves for the love of God" (Catechism, 1822). This is Christ's “new commandment": that you love one another as I have loved you (Jn 15:12). 
5. Human virtues
“Human virtues are firm attitudes, stable dispositions, habitual perfections of intellect and will that govern our actions, order our passions, and guide our conduct according to reason and faith. They make possible ease, self‑mastery, and joy in leading a morally good life" (Catechism, 1804). These virtues “are acquired by human effort. They are the fruit and seed of morally good acts" (Catechism, 1804). 
Among the human virtues there are four that are called cardinal virtues because all of the others are grouped around them. These are prudence, justice, fortitude, and temperance (see Catechism, 1805).
• Prudence “is the virtue that disposes practical reason to discern our true good in every circumstance and to choose the right means of achieving it" (Catechism, 1806). It is “right reason in action,"  says St. Thomas Aquinas.
• Justice “is the moral virtue that consists in the constant and firm will to give their due to God and neighbor" (Catechism, 1807). 
• Fortitude “is the moral virtue that ensures firmness in difficulties and constancy in the pursuit of the good. It strengthens the resolve to resist temptations and to overcome obstacles in the moral life. The virtue of fortitude enables one to conquer fear, even fear of death, and to face trials and persecutions. It disposes one even to renounce and sacrifice his life in defense of a just cause" (Catechism, 1808). 
• Temperance “is the moral virtue that moderates the attraction of pleasures and provides balance in the use of created goods. It ensures the will's mastery over instincts" (Catechism, 1809). A temperate person directs his sensible appetites towards what is truly good and does not let himself be controlled by his passions (see Sir 18:30). In the New Testament it is called “moderation" or “sobriety" (see Catechism, 1809).
The saying in medio virtus , "virtue lies in the middle," with respect to the moral virtues means that virtue consists in a mean between a defect and an excess.  However, in medio virtus is not a call to mediocrity. Virtue is not a middle term between two or more vices, but a rightness of will—a summit, as it were—which is opposed to all the abysms of the vices. 
6. Virtues and grace. The Christian virtues
The wounds left by original sin on human nature make the acquisition and exercise of human virtues difficult (see Catechism, 1811).  To acquire and live them, Christians count on God's grace, which heals human nature.
Grace elevates human nature to participate in the divine nature. At the same time grace elevates the human virtues to the supernatural order (see Catechism, 1810), leading the human person to act according to right reason illumined by faith: in a word, to imitate Christ. In this way, human virtues become Christian virtues . 
7. The gifts and fruits of the Holy Spirit
“The moral life of Christians is sustained by the gifts of the Holy Spirit. These are permanent dispositions which make man docile in following the promptings of the Holy Spirit" ( Catechism, 1830).  The gifts of the Holy Spirit are (see Catechism, 1831):
1st the gift of wisdom: in order to understand and judge rightly about God's plans;
2nd the gift of understanding: in order to penetrate into the truth about God;
3rd the gift of counsel: to recognize and further God's plans in particular acts;
4th the gift of fortitude: to overcome difficulties in Christian life;
5th the gift of knowledge: to grasp the order of created reality;
6th the gift of piety: to behave as children of God and in a fraternal manner towards all our brothers and sisters, being other Christs;
7th the gift of fear of the Lord: to reject all that could offend God, as a child would reject, through love, all that might offend his father.
The fruits of the Holy Spirit “are perfections that the Holy Spirit forms in us as the first fruits of eternal glory" ( Catechism, 1832). These are acts which the action of the Holy Spirit produces in our soul in a habitual way. The tradition of the Church enumerates twelve fruits: “love, joy, peace, patience, forbearance, kindness, goodness, faithfulness, gentleness, modesty, self-control, chastity" (see Gal 5:22–23).
8. The influence of the passions in moral life
By the substantial union of our body and soul, our spiritual life—intellectual knowledge and free choice of the will—is subject to the influence of our feelings. This influence is manifested in the passions, which are “movements of the sensitive appetite that incline us to act or not to act in regard to something felt or imagined to be good or evil" ( Catechism, 1763). The passions are movements of the sensible appetite (irascible and concupiscible). They can also be called, in the broad sense, “sentiments" or “emotions." 
Love, anger, fear, etc. are examples of passions. “The most fundamental passion is love, aroused by the attraction of the good. Love causes a desire for the absent good and the hope of obtaining it; this movement finds completion in the pleasure and joy of the good possessed. The apprehension of evil causes hatred, aversion, and fear of the impending evil; this movement ends in sadness at some present evil, or in the anger that resists it" ( Catechism, 1765).
The passions have a great influence on our moral life. “In themselves passions are neither good nor evil" ( Catechism, 1767). “Passions are morally good when they contribute to a good action, evil in the opposite case" (Catechism, 1768).  Human perfection requires having one's passions regulated by reason and controlled by the will.  Since original sin, our passions are no longer subject to the control of reason and they frequently push us towards something that is not good.  To channel them towards the good in a constant or habitual manner requires ascetical struggle and the help of grace, which heals the wounds of sin.
The will, if it is good, makes use of the passions, ordering them towards the good.  In contrast a bad will, which stems from selfishness, succumbs to disordered passions or uses them for evil (see Catechism, 1768).
Catechism of the Catholic Church, 1762–1770, 1803–1832 and 1987–2005.
St. Josemaria, homily “Human Virtues," in Friends of God, nos. 73–92.
St. Thomas Aquinas, Summa Theologiae , I-II, qq. 22ff; 109-114; II-II, qq. 1-27; 47-62; 139-143.
 This vocation “depends entirely on God's gratuitous initiative, for he alone can reveal and give himself. It surpasses the power of human intellect and will, as that of every other creature (see 1 Cor 2:7–9)" (Catechism, 1998).
 St. Thomas Aquinas, Summa Theologiae, II–II, q. 24, a.3, ad 2.
 Second Vatican Council, Const. Gaudium et Spes, 22. See Rom 8:14–17; Gal 4:5–6; 1 Jn 3:1.
 Every created gift proceeds from the uncreated Gift, the Holy Spirit. God's love has been poured into our hearts through the Holy Spirit who has been given to us (Rom 5:5. See Gal 4:6).
 One must distinguish between habitual grace and actual graces , “which refer to God's interventions, whether at the beginning of conversion or in the course of the work of sanctification" ( Catechism, 2000).
 “Justification is not only the remission of sins, but sanctification and renovation of the interior man" (Council of Trent: DZ 1528).
 In adults, this step is the fruit of God's impulse (actual grace) and human freedom. “Moved by grace, man turns toward God and away from sin, thus accepting forgiveness and righteousness from on high [sanctifying grace]" ( Catechism, 1989).
 This is a truth our Lord has wanted to remind us of, with special force, through the teachings of Saint Josemaria, since October 2, 1928. As the Church proclaimed in the Second Vatican Council (1962–65): “all Christians in any state or walk of life are called to the fullness of Christian life and to the perfection of love" ( Lumen Gentium, 40).
 See St. Thomas Aquinas, Summa Theologiae, III, q.2, a.12, c.
 See St. Josemaria, Christ Is Passing By , 104.
 But grace “is not in the slightest way a rival of our freedom when this freedom accords with the sense of the true and the good that God has put in the human heart" ( Catechism, 1742). On the contrary, “grace responds to the deepest yearnings of human freedom, calls freedom to cooperate with it, and perfects freedom" ( Catechism, 2022).In the present state of human nature, wounded by sin, grace is necessary to live constantly in accord with the natural moral law.
 Christ Is Passing By, 9.
 To gain God's grace we can also have recourse to the intercession of our most holy Mother Mary, the Mediatrix of all grace, and also of St. Joseph, our guardian angels, and the saints.
 Vices, on the contrary, are moral habits which result from bad acts and incline one to repeat them and to grow worse.
 In a way analogous to how the human soul operates through its potencies (understanding and will), the Christian in the state of grace acts through the theological virtues, which are, as it were, potencies of the “new nature" elevated by grace.
 Second Vatican Council, Const. Dei Verbum, 5.  Faith is manifested in deeds: a living faith works through charity (Gal 5:6), while faith apart from works is dead (Jas 2:26), although the gift of faith remains in one who has not sinned directly against it (see Council of Trent: DZ 1545).
 See Heb 10:23; Tit 3:6–7. “The virtue of hope responds to the aspiration to happiness which God has placed in the heart of every man" ( Catechism, 1818): it purifies and elevates this aspiration and protects us from discouragement; it opens our heart to the prospect of eternal beatitude, protects us from selfishness and leads us to happiness (see ibid.).
We should hope for the glory of heaven promised by God to those who love him (see Rom 8:28–30) and who do his will (see Mt 7:21), certain that with God's grace we will be able to persevere to the end (see Mt 10:22) (see Catechism, 1821).
 Charity is superior to all the other virtues (see 1 Cor 13:13). If I . . . have not love, I am nothing . . . I gain nothing (1 Cor 13:1–3).
“The practice of all the virtues is animated and inspired by charity" ( Catechism, 1827). It is the form of all the virtues: it “informs" or “vivifies" them because it directs them to the love of God; without charity, the other virtues are “dead."
Charity purifies our human faculty of loving and elevates it to the supernatural perfection of divine love (see Catechism, 1827). There is an order of charity. Charity is also shown in fraternal correction (see Catechism, 1829).
 As is explained in the next section, the Christian develops these virtues with the help of God's grace which, as it purifies nature, gives strength to practice them, and orders them to a higher end.
 St. Thomas Aquinas, Summa Theologiae , II–II, q.47, a.2, c.Prudence leads one to judge rightly about how to act: it does not dissuade one from acting. “It is not to be confused with timidity or fear, nor with duplicity or dissimulation. It is called auriga virtutum (the charioteer of the virtues); it guides the other virtues by setting rule and measure. With the help of this virtue we apply moral principles to particular cases without error and overcome doubts about the good to achieve and the evil to avoid" ( Catechism, 1806).
 Man cannot give God what is owed to him or what is just in the strict sense. Therefore, justice towards God is called more properly “the virtue of religion," “since for God it is sufficient that we fulfill these duties insofar as we are able to" (St. Thomas Aquinas, Summa Theologiae, II-II, q.57, a.1, ad 3).
 In the world you have tribulation; but be of good cheer, I have overcome the world (Jn 16:33).
 For example, laboriousness consists in working as much as one should, which is a mean between an excess and a lack. Opposed to laboriousness is to work less than one should, wasting time, etc. And also opposed to laboriousness is working without measure, without respect for all the other things which one also has to do (duties of piety, attention to family, necessary and just rest, charity, etc.).
 The principle in medio virtus is valid only for the moral virtues, which have as their object the means for attaining a goal, and in the means there is always a measure. This is not true of the theological virtues (faith, hope and charity), which have God directly as their object. Therefore no excess is possible with them: it is impossible to “hope in God too much," or “to love him too much."
 Human nature has been wounded by sin. As a result it has inclinations which are not natural, but are the consequence of sin. Just as limping is not natural, but the result of an infirmity, and it would not be natural even if everyone limped, the wounds in the soul left by original sin and by personal sins are not “natural" either: the tendency to pride, to laziness, to sensuality, etc. With the help of grace and with personal effort these wounds can be healed, so that the person becomes and acts as befits his or her nature as a child of God. This “health" is gained through virtues. Similarly, the “sickness"is aggravated by vices.
 In this sense, there is a prudence which is a human virtue, and a supernatural prudence, which is a virtue infused by God into the soul, together with grace. For the supernatural virtue to be able to produce fruit—good acts—it needs the corresponding human virtue (the same thing happens with the other cardinal virtues: the supernatural virtue of justice requires the human virtue of justice; and the same with fortitude and temperance). In other words, Christian perfection—sanctity—requires and involves human perfection.
 Here, to help in understanding the function of the gifts of the Holy Spirit in the moral life, we can add the following classic explanation. Just as human nature has certain powers (intelligence and will) which permit it to carry out the operations of understanding and willing, so also does nature elevated by grace have powers which permit it to accomplish supernatural acts. These powers are the theological virtues (faith, hope and charity). They are like the oars of a boat, which permit it to move in the direction of its supernatural end. Nevertheless, this end surpasses us to such an extent that the theological virtues are not sufficient to attain it. God grants us, together with grace, the gifts of the Holy Spirit, which are new perfections of the soul that enable it to be moved by the Holy Spirit himself. They are like the sail in a boat that enables it to move by the wind's force. The gifts perfect us by making us more docile to the action of the Holy Spirit.
 One can also speak of supra-sensible or spiritual “sentiments" or “emotions," which are not properly “passions" because they do not bring with them movements of the sensitive appetite.
 For example, there is such a thing as good anger, which is to become indignant in the face of evil, and there is also bad anger, which is uncontrolled or which impels one towards evil (as is the case with vengeance); there is a good fear and a bad fear, which prevents one from doing the good; etc.
 See St. Thomas Aquinas, Summa Theologiae, I–II, q.24, aa. 1 and 3.
 At times the passions can come to dominate a person to such an extent that one's moral responsibility is reduced to a minimum.
 “Moral perfection consists in man's being moved to the good not by his will alone, but also by his sensitive appetite, as in the words of the psalm: 'My heart and flesh sing for joy to the living God' (Ps 84:3)" (Catechism, 1770). “The passions are bad if our love is bad, good if it is good" (St. Augustine, De Civitate Dei, 14:7).