On the forgivess of Sins:

The purpose of the advent of the Saviour, when He gave us His life giving commandments as purifying remedies in our passionate state, was to cleanse the soul from the damage done by the first transgression and bring it back to its original state.

Behold, baptism gives freely and demands nothing except faith; but if a man repents his sins after baptism, God does not forgive him freely, but demands works, suffering, sorrows, contrition, tears, a long time of mourning - and then forgives. The Lord forgave the theif freely, merely for his confession uttered on the cross, and promised him the Kingdom; but in the case of the woman who had sinned He demanded also faith and tears.

St. Issac the Syrian, Directions in Spiritual Training