What a Sinner is Incapable of Doing

I once heard a spiritual man [probably St. John of the Cross] say that he was not so much astonished at the things done by a soul in mortal sin as at the things not done by it. May God, in His mercy, deliver us from such great evil for there is nothing in the whole of our lives so thoroughly deserves to be called evil as this, since it brings endless and eternal evils in its train. 
— St. Teresa of Avila, Interior Castle Page 50-51
Hat tip to St. Peter's List