Tear doubt out of your heart! Never allow doubt to hinder you from praying to God by perchance thinking to yourself, “How can I ask anything from the Lord, how can I receive anything from him since I have sinned so much against him?” Never think like this! Instead, turn to the Lord with your whole heart. Pray to him without wavering and you will come to know his great mercy. He will never desert you. He will fulfill your heart’s request because God is not like men, who harbor grudges. No, he does not remember evil, and he has compassion for what he has made.
Source: The Early Christians