How do we know that repentance is required for salvation?

Scriptural references such as Acts 3:19 exhort believers to repent and be converted, highlighting that true repentance is crucial to receiving forgiveness and new life in Christ. This idea is underscored by the Heidelberg Catechism, which states that we are naturally prone to hate God and our neighbor, requiring a divine work of grace to enable us to turn genuinely towards God. Repentance entails both sorrow for sin and a commitment to forsake it, reinforced by the transformative work of the Holy Spirit.