What does Psalm 51:17 mean?

David could have offered God a thousand sacrifices, but he knew the sacrifices God looks for are a broken spirit and a broken and contrite heart. David offered God a broken spirit and a broken and contrite heart when he implored God to forgive his sin. Isaiah 57:15 reinforces David's words by quoting God as saying, "I dwell in the high and holy place, and also with him who is of a contrite and lowly spirit, to revive the spirit of the lowly, and to revive the heart of the contrite."

Jesus recounted the story of a tax collector and a Pharisee to illustrate this truth (Luke 18:9–14). The two men entered the temple to pray. The Pharisee's heart was proud. He filled his prayer with boasting about his religious works (Luke 18:11–12), whereas the tax collector was too humble and contrite even to lift his eyes toward heaven. He simply beat his breast and said, "God be merciful to me, a sinner" (Luke 18:13). Jesus stated that the tax collector went home justified, rather than the haughty Pharisee. He concluded: "For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted" (Luke 18:14).