Thomas Aquinas

“ But the intrinsic cause on our part must needs be meditation or contemplation. For it was stated above (A [1] ) that devotion is an act of the will to the effect that man surrenders himself readily to the service of God. Now every act of the will proceeds from some consideration, since the object of the will is a good understood. Wherefore Augustine says (De Trin. ix, 12; xv, 23) that "the will arises from the intelligence." Consequently meditation must needs be the cause of devotion, in so far as through meditation man conceives the thought of surrendering himself to God's service. ”

“ Secondarily devotion is caused as stated (A [3] ) , by the consideration of one's own failings; for this consideration regards the term from which man withdraws by the movement of his devout will, in that he trusts not in himself, but subjects himself to God. This consideration has an opposite tendency to the first: for it is of a nature to cause sorrow directly (when one thinks over one's own failings) , and joy accidentally, namely, through hope of the Divine assistance. ”

“ Chief among these is the humanity of Christ, according to the words of the Preface [*Preface for Christmastide] , "that through knowing God visibly, we may be caught up to the love of things invisible." ”