Yes, God must make an account of Himself, some believe. Others, looking to Christ, understand that God has already given an account of Himself, offering in advance the source of forgiveness for this sin and every sin. There is no evil that God cannot overcome with His love. There is no human person who can put himself beyond the reach of God's mercy in Christ. How does God do this? Through the Church.
In the Apostles and first Christians gathered around them, God formed his Holy Church through the sending of the Spirit, like a dove as Saint John the Baptist describes, that through her the waters of baptism might flow abundantly until the end of the world.
"From the very day of Pentecost the Church has celebrated and administered holy Baptism. Indeed St. Peter declares to the crowd astounded by his preaching: '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.' The apostles and their collaborators offer Baptism to anyone who believed in Jesus: Jews, the God-fearing, pagans. Always, Baptism is seen as connected with faith: 'Believe in the Lord Jesus, and you will be saved, you and your household,' St. Paul declared to his jailer in Philippi. And the narrative continues, the jailer 'was baptized at once, with all his family.' " (CCC 1226)
Repentance was, and is, a necessary condition for reception of God's saving Spirit of divine love. What is this repentance required of us if we are to be saved by the waters of Baptism?
"Interior repentance is a radical reorientation of our whole life, a return, a conversion to God with all our heart, an end of sin, a turning away from evil, with repugnance toward the evil actions we have committed. At the same time it entails the desire and resolution to change one's life, with hope in God's mercy and trust in the help of his grace. This conversion of heart is accompanied by a salutary pain and sadness which the Fathers called animi cruciatus (affliction of spirit) and compunctio cordis (repentance of heart)." (CCC 1431)
We must turn, then, away from all things contrary to God's holy will and begin more and more, with His help to conform our thoughts, words, actions, our very heart, to His holy will.
"The movement of return to God, called conversion and repentance, entails sorrow for and abhorrence of sins committed, and the firm purpose of sinning no more in the future. Conversion touches the past and the future and is nourished by hope in God's mercy." (CCC 1490)
How can we be converted again after baptism in the case of the most egregious evil? How can the waters of Baptism be fully restored to us? Through the sacrament of Confession, which is necessary for forgiveness of grave or serious sin. Reconciliation with Christ and the Church must take place through confession if we have committed mortal sin.
"Individual, integral confession and absolution remain the only ordinary way for the faithful to reconcile themselves with God and the Church, unless physical or moral impossibility excuses from this kind of confession." There are profound reasons for this. Christ is at work in each of the sacraments. He personally addresses every sinner: "My son, your sins are forgiven." He is the physician tending each one of the sick who need him to cure them. He raises them up and reintegrates them into fraternal communion. Personal confession is thus the form most expressive of reconciliation with God and with the Church. (CCC 1484)
Thus the Church does the work of God in this and every age: forgiving sins through the gift of the Spirit both in Baptism for the first time and over again for conversion of heart for sins committed after our Baptism in the sacrament of Confession.
"Christ sent his apostles so that 'repentance and forgiveness of sins should be preached in his name to all nations.' '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.' The mission to baptize, and so the sacramental mission, is implied in the mission to evangelize, because the sacrament is prepared for by the word of God and by the faith which is assent to this word:
This forgiveness with God and with one another restores unity and healing to the Body of Christ, one of the marks of the true Church of God. The Church is the source both of the one Baptism and the one source of forgiveness through the Spirit.