Thomas Aquinas

“ Consequently, by reason of human nature alone can predestination be attributed to Christ. Wherefore Augustine says (De Praedest. Sanct. xv) : "This human nature of ours was predestinated to be raised to so great, so lofty, so exalted a position, that it would be impossible to raise it higher." Now that is said to belong to anyone as man which belongs to him by reason of human nature. Consequently, we must say that "Christ, as Man, was predestinated the Son of God." ”

“ Now, that man is God, and that God is man, is something done in time by God through the grace of union. Nor can it be said that God has not from eternity pre-ordained to do this in time: since it would follow that something would come anew into the Divine Mind. And we must needs admit that the union itself of natures in the Person of Christ falls under the eternal predestination of God. ”

“ For although it is natural to that Person, considered in Himself, to be the Son of God in power, yet this is not natural to Him, considered in the human nature, in respect of which this befits Him according to the grace of union. ”