Acts 5:31 Him God hath exalted with his right hand to be a Prince and a Saviour, for to give repentance to Israel, and forgiveness of sins.
Peter preaches once again about Jesus, that God raised Him up and exalted Him to the highest place in the universe. From that position as king of kings and king of kingdoms He is able to promise us repentance and forgiveness.
Genuine repentance must be given to us as a gift and a blessing. Repentance is not something we can work up or come up with on our own. Repentance is a promise from God. The Holy Spirit works repentance in us through the hearing of Law and Gospel in the Word. He convicts us of sin and guilt, grants godly sorrow, and stirs up the need and desire for the Gospel. We ask the Lord to give us a repentant heart, for our own ”doing penance” doesn’t make it happen. So He promises to give repentance.
After and along with the gift of repentance He gives the forgiveness of sins. This is the promise: the gift of real and true and everlasting forgiveness. The Spirit through the Word promises both repentance and forgiveness. He creates the need for repentance and forgiveness and then fills that need. He ministers that need and fulfills the promise daily, for the Christian life is one of daily repentance for sin and faith for forgiveness of sin.