1. In the life and ministry of Jesus
When John the Baptist began his ministry by the River Jordan, he called people to a baptism of repentance for the forgiveness of sins in anticipation of the coming of the Kingdom of God (Matthew 3:1; Luke 3:3). His message was one of preparation for the ministry of the one who would not baptize with water, but with the Holy Spirit (Matthew 3:11; Mark 1:8; Luke 3:16; John 1:26-27).
When Jesus was baptized by John, it became evident that his baptism was not a sign of repentance, but a moment of recognition and affirmation by the Spirit of God (Matthew 3:16-17; Mark 1:9-11; Luke 3:21-22; John 1:3-34). Jesus was the one whom John's ministry was preparing people, he was "the Lamb of God, who takes away the sins of the world" (John 1:29).
As Jesus began his ministry, he too preached repentance and declared the coming of the Kingdom of God (Matthew 4:17; Mark 1:15; Luke 5:32). In his life and work, the Kingdom was becoming a reality (Matthew 11:4-6; Isaiah 35:5-7). In his death, provision was made for the forgiveness of sins, so that anyone who believes may become a citizen of the Kingdom; a Kingdom which will finally be revealed in its fulness when Jesus comes again as judge and King (Matthew 24-25; Revelation 21-22).
2. As a response to the work of Christ
If we are to experience personally the forgiveness offered by the Atonement, we must respond to the grace of God as revealed in Christ's sacrificial act (Luke 24:47; Acts 2:38; Acts 3:19). That response is repentance and faith, which are the twin elements of one action. They may be distinct or woven into one experience, but each is indispensable and neither is possible without the accompanying grace of God.
Our repentance is a gift of grace through the Holy Spirit. Although often accompanied by sorrow, it is essentially joyful, not morbid, because it is our response to the good news of salvation (2 Corinthians 7:10). The Spirit stimulates within us a desire for a change of direction. We become more aware of our sinfulness and this moves us, not down into despair, but upwards towards God. We long to turn away from our selfishness and sin and towards the self-giving love of God. We are drawn to confess our sins, renounce selfish lifestyles and to make restitution for the sins of the past.