If you have transgressed […], and have sinned, do not despair. But at that very moment, confess your sin and fall down with humility before the compassionate eyes of God and ask mercy with the voice of the publican, “God be merciful to me a sinner!” (Lk. 18:13), and your sins will be forgiven you.
– St. Tikhon of Zadonsk
Hat tip: handmaid leah