And Peter said to them, "Repent, and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins; and you shall receive the gift of the Holy Spirit."
When Peter said these words, he was filled with the Holy Spirit that had been lavishly poured out upon the Church at Pentecost. His audience had been "cut to the heart"1 by his preaching about Jesus Christ and the fulfillment of the promised Spirit, and they begged of him to tell them what they must do next. At this pivotal moment in the history of the Church, Peter specifically called for repentance and conversion. From this scene alone we can see the importance of what Peter required of them. In fact, conversion is a main theme throughout the entire Old and New Testaments.2 It is certainly no coincidence then that the Church would take up this theme in so many of her catechetical documents.3 But, what is this conversion that is so emphasized by the Scriptures and the Church? How does one come to be so "cut to the heart" that they long to know what they must do to follow God? Before we can heed the call of Peter and follow in his footsteps, it is imperative that we know the nature of conversion, and the means with which to effect it—both in our lives and in the lives of others.
The General Directory for Catechesis (GDC) states on at least ten different occasions that conversion to Christ means adherence to His person and following in his footsteps.4 Article no. 53 states:
In proclaiming the Good News of Revelation to the world, evangelization invites men and women to conversion and faith. The call of Jesus, "Repent and believe in the Gospel", (Mk 1:15) continues to resound today by means of the Church's work of evangelization. The Christian faith is, above all, conversion to Jesus Christ, full and sincere adherence to his person and the decision to walk in his footsteps. Faith is a personal encounter with Jesus Christ making of oneself a disciple of him. This demands a permanent commitment to think like him, to judge like him and to live as he lived. In this way the believer unites himself to the community of disciples and appropriates the faith of the Church.Catechesi Tradendae (CT) also takes up this language of "adherence"5 and states that the specific aim of catechesis is to bring about and to nurture this act of faith in God:
To put it more precisely: within the whole process of evangelization, the aim of catechesis is to be the teaching and maturation stage, that is to say, the period in which the Christian, having accepted by faith the person of Jesus Christ as the one Lord and having given Him complete adherence by sincere conversion of heart, endeavors to know better this Jesus to whom he has entrusted himself: to know His "mystery," the kingdom of God proclaimed by Him, the requirements and promises contained in His Gospel message, and the paths that He has laid down for anyone who wishes to follow Him. (Article 20, paragraph 3)It goes on to make an interesting caveat. While it is true that being a Christian means saying, "Yes" to Jesus, we must keep in mind that there are two levels to this response: "surrendering to the word of God and relying on it," and, "endeavoring to know better and better the profound meaning of this word."6 One is left to wonder: Is this "word of God" to which we give our adherence the person of Jesus Christ or the deposit of faith he has given us? Since the nature of conversion is a turning of one’s mind and heart7 towards the person of Christ and his message, one could say that the reference is to both. The heart of catechesis is a person, and a person filled with truth.8 "To believe" has thus a twofold reference: to the person, and to the truth (CCC, no. 177).
As for the means for conversion, Scripture presents a variety. Conversion is:
- By God — 1Ki 18:37; Joh 6:44; Ac 21:19.
- By Christ — Ac 3:26; Ro 15:18.
- By the power of the Holy Spirit — Pr 1:23.
- Is of grace — Ac 11:21,23.
- Follows repentance — Ac 3:19; 26:20.
- Is the result of faith — Ac 11:21.
- Through the instrumentality of
We have already seen how Peter’s preaching was the catalyst for the conversion of his audience. It is only right that the Church stands in the person of Peter and effects conversions in the same way. Remarkably, we see all three means for conversion in Peter’s words. We see catechesis in his proclamation of the resurrection of Christ and in his affirmation that what has just taken place is the fulfillment of Old Testament prophecy.11 We see liturgy in his command that they be baptized "in the name of Jesus Christ for the forgiveness of your sins."12 Finally, we see community in the fact that Peter’s message is not just for one person, or even just for the crowd that was present. Instead, "the promise is to you and to your children and to all that are far off, every one whom the Lord our God calls to him."13 All are given the same command and are brought together by their response to it, regardless of language or nationality.14 The reception of Baptism means entrance into a community15, a "body" whose parts all contribute to the well-being of each other.16 "For all the baptized, children or adults, faith must grow after Baptism," and this faith "needs the community of believers."17
From all this, we have now established the nature of and means for conversion. Conversion to Christ means adherence to His person and following in his footsteps. This adherence and following is achieved through a variety of ways: the Trinitarian God, grace, faith, the Scriptures, liturgy, the ecclesial community, and a robust catechesis centered on Christ. With so much to do, and so much at stake, the conversion of souls is a grand undertaking. But, we know that it is the responsibility of us all, and that God will not abandon us in this endeavor. When Jesus Christ told the apostles to "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you" he also said that he would always be with us, until the end of the age.18 He said that he would give us the Spirit of truth to be with us forever and that this Spirit would teach us all things19 and guide us into all truth.20 The Church received this Spirit at Pentecost, and this same Spirit empowers us to be "ambassadors for Christ" in the "ministry of reconciliation."21
- - - "Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, 'Brethren, what shall we do?'" (Acts 2:37; all scripture citations from the RSV).
 All the passages of Scripture that speak of repentance and conversion are perhaps too numerous to list here. See Reuben Archer Torrey, "Conversion" in Torrey’s New Topical Textbook.
 Cf. Catechism of the Catholic Church, nos. 160, 545, 981, 1036, 1422-1423, 1428, 1430-1433, 1435, 1797, 2608-2609; General Directory for Catechesis, nos. 29, 47-48, 53, 55-58, 61-63, 69, 80, 82, 85, 88-90, 101, 149, 152, 157, 194, 203-204, 254, 283; Catechesi Tradendae, nos. 19, 20, 49, 51-52.
 Cf. nos. 53, 55, 56, 63, 80, 85, 92, 144, 221, 276.
 Cf. nos. 19, 20, 24, 57.
 CT, no. 20. Note that the GDC presents a slightly different two-fold structure of this "yes" response to God: "a trustful abandonment to God and a loving assent to all that he has revealed to us" (no. 54).
 Ibid., nos. 19, 20, 25, 26, 29, 36, 38, 72.
 Ibid., no. 5.
 Reuben Archer Torrey, “Conversion” in Torrey’s New Topical Textbook.
 Liturgy: GDC, nos. 51, 71, 85, 87, 95, 108, 122; CT, nos. 23, 27, 30, 48. Community: GDC, nos. 27, 48-53, 61, 67-72, 84, 86-91, 106, 141, 143, 158-159, 174, 180, 183, 186, 217-221, 253-259, 263; CT, nos. 24, 67, 72. Catechesis: read GDC and CT in their entirety, cf. CCC, nos. 4-10, 427, 983, 1697, 2226, 2688.
 Cf. Acts 2:14-36.
 Acts 2:38.
 Acts 2:39.
 Acts 2:5-6.
 After Peter’s audience was baptized, they "devoted themselves to the apostles' teaching and fellowship, to the breaking of bread and the prayers. [. . .] And all who believed were together, and had all things in common; and they sold their possessions and good and distributed them to all, as any had need. And day by day, attending the temple together and breaking bread in their homes, they partook of food with glad and generous hearts, praising God and having favor with all the people. And the Lord added to their number day by day those who were being saved" (Acts 2:42-47).
 Cf. 1 Cor 12:24b-26; 1 Thes 5:11.
 CCC, nos. 1253-1254.
 Mt 28:19-20.
 Jn 14:16-17,26.
 Jn 16:13.
 2 Cor 5:18-20.