This song is varied in the notes that is plays but it strikes three dominant chords in a particular progression: penitence (sorrow) for sin, pardon of sin, and power over sin. The chords must always be played in that order.
The psalmist understood that the sacrifices and rituals required by the law were inadequate by themselves to save. They are no substitute for obedience from the heart. Furthermore, the only power to over from the heart is to have God’s law written in our hearts.