Repentance as Jesus characterized it…involves a recognition of one’s utter sinfulness and a turning from self and sin to God (cf. 1 Thessalonians 1:9). Far from being a human work, it is the inevitable result of God’s work in a human heart. And it always represents the end of any human attempt to earn God’s favor. It is much more than a mere change of mind – it involves a complete change of heart, attitude, interest, and direction. It is a conversion in every sense of the word.
John MacArthur