The guilt produced by the Pharisaic system may have contributed to the power of John the Baptist's ministry. He had a ready audience because people wanted to be freed from the burden of sin.
Jesus explained to Nicodemus that the only way to be pure in heart is to be born with a new heart.
David knew this principle as well.
"[Happy] is the man unto whom the Lord imputeth not iniquity" (Ps. 32:2