What is the heart of man according to the Bible?

According to the Bible, particularly in Matthew 15:19, the heart of man is the source of evil thoughts and actions. Jesus states, 'Out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies.' This diagnosis reveals the need for a transformed heart, as our natural state is marked by sinfulness and separation from God. Understanding this helps believers recognize the depth of their sin and the necessity of Christ's redemptive work. Only through a new birth in Christ can one's heart be transformed, leading to a life that honors God.