Luke 18:13-14 "But the tax collector stood at a distance. He would not even look up to heaven, but beat his breast and said, 'God, have mercy on me, a sinner.' I tell you that this man, rather than the other, went home justified before God. For everyone who exalts himself will be humbled, and he who humbles himself will be exalted."
These verses, from the well-known story of the Pharisee and the tax collector praying in the temple, reveals the prayer that allows us to enter into a relationship with God: "God, have mercy on me, a sinner." The tax collector was honest with God about his sin. He humbled himself, repented, and acknowledged his need of God's mercy. God answered his prayer and saved him.