Thomas Aquinas

“ Therefore when we say that word is knowledge, the term knowledge does not mean the act of a knowing intellect, or any one of its habits, but stands for what the intellect conceives by knowing. Hence also Augustine says (De Trin. vii, 1) that the Word is "begotten wisdom;" for it is nothing but the concept of the Wise One; and in the same way It can be called "begotten knowledge." Thus can also be explained how "to speak" is in God "to see by thought," forasmuch as the Word is conceived by the gaze of the divine thought. Still the term "thought" does not properly apply to the Word of God. ”

“ The nature is also included indirectly in the name of the person; for person is an individual substance of a rational nature. Therefore the name of a divine person, as regards the personal relation, does not imply relation to the creature, but it is implied in what belongs to the nature. Yet there is nothing to prevent its implying relation to creatures, so far as the essence is included in its meaning: for as it properly belongs to the Son to be the Son, so it properly belongs to Him to be God begotten, or the Creator begotten; and in this way the name Word imports relation to creatures. ”

“ The Arians, who sprang from Origen, declared that the Son differed in substance from the Father. Hence, they endeavored to maintain that when the Son of God is called the Word, this is not to be understood in a strict sense; lest the idea of the Word proceeding should compel them to confess that the Son of God is of the same substance as the Father. For the interior word proceeds in such a manner from the one who pronounces it, as to remain within him. But supposing Word to be said metaphorically of God, we must still admit Word in its strict sense. ”