In the beginning at Mass, we confess to God that we have sinned in our thoughts and in our words, in what we have done and in what we have failed to do. We see that thoughts, words, and deeds all originate from the heart. If we can keep our hearts pure, we shall be clean. Therefore, let Jesus rule our hearts. The heart is surely the greatest possible gift we can give to God, a gift he would appreciate and be please with.