CCC 1855
Life in Christ›SECTION ONE MAN'S VOCATION LIFE IN THE SPIRIT›CHAPTER ONE THE DIGNITY OF THE HUMAN PERSON›IV. The Gravity of Sin: Mortal and Venial Sin
Mortal sin destroys charity in the heart of man by a grave violation of God's law; it turns man away from God, who is his ultimate end and his beatitude, by preferring an inferior good to him. Venial sin allows charity to subsist, even though it offends and wounds it.