"Keep in your hearts the words of God that you hear. The word of God is our heart's food. When we hear this word and do not retain it in our memories, it is as if we are taking food into an upset stomach: we throw it up. We despair for the life of one who does not retain nourishment. You must fear the danger of eternal death, then, if you do not keep the words of life, the nourishment that is righteousness, in your hearts."
Gregory the Great