It often happens that Satan will insidiously commune with you in your heart and say: "Think of the evil you have done; your soul is full of lawlessness, you are weighed down by many grievous sins." Do not let him deceive you when he does this and do not be led to despair on the pretext that you are being humble. You should answer: "I have God's assurance, for He says:
What was the purpose of His descent to earth except to save sinners, to bring light to those in darkness and life to the dead?" St. Makarios of Egypt