Saint Anselm

“ Since, therefore, infallible reason has brought us to this necessary conclusion, that the Divine and human natures must unite in one person, and that this is evidently more fitting in respect to the person of the Word than the other persons, we determine that God the Word must unite with man in one person. ”

“ It is, that for the Son to pray to the Father is more proper than for any other person of the Trinity to supplicate his fellow. Moreover, man, for whom he was to pray, and the devil, whom he was to vanquish, have both put on a false likeness to God by their own will. Wherefore they have sinned, as it were, especially against the person of the Son, who is believed to be the very image of God. ”

“ Now must we inquire further, in what person God, who exists in three persons, shall take upon himself the nature of man. For a plurality of persons cannot take one and the same man into a unity of person. Wherefore in one person only can this be done. ”