What does the Bible say about mortification of sin?

The biblical concept of mortification involves not only the external rejection of sin but addressing the root causes that lead to spiritual decline. As seen in Psalm 64:18, a believer must confront and forsake iniquity in the heart to be heard by the Lord. This thorough approach aims to bring the whole being under subjection to God, recognizing that without true mortification of sin, there can be no genuine return to God. It requires a conscious effort from the believer in cooperation with the power of the Holy Spirit, emphasizing that while the believer must engage in this process, the true effectiveness comes from divine assistance. Only through the Holy Spirit can one seek the heart's renewal and healing.