«SON OF GOD». — This term, in current usage, may designate every creature insofar as it is produced by God and watched over by his providence; or the rational creature insofar as, through Grace, it is destined to enjoy God in the beatific vision (= adopted son); or finally the natural Son of God, he who proceeds from God the Father by way of generation, and is therefore really distinct from him, while sharing with him the same divine nature. In this sense the term is to be understood when one speaks of the S. of G. as the second person of the Most Holy Trinity. Thus it was defined at the Council of Nicaea (325) against the heresy of Arius, who maintained that the Word, that is, the S. of G., was the first and most exalted creature of God (v. CONSOSTANZIALE).
The doctrine of the Church, already intimated in the Old Testament, appears with complete clarity in the books of the New Testament, where the S. of G. is revealed to us in the person of Jesus Christ. For he is expressly called the proper S. of G. (Rom. 8:32), the unique one (Mt. 3:17; 17:5), the only-begotten (Io. 1:14, 18; 3:16), the firstborn (Col. 1:15), the true one (I Io. 5:20); appellations that absolutely exclude any filiation other than the natural one.
Jesus Christ himself always speaks of God as his father and the father of men, but he lets it be understood that he is his father in a wholly particular and exclusive manner,
because he always distinguishes divine fatherhood with regard to himself from that toward men (My Father, your Father: cf. Lc. 22:29; Mt. 10:33; 6:32; Io. 20:17). If our relations with God are those of adopted children, Christ’s, on the other hand, are those of a natural son; this, moreover, is evident from those testimonies in which Christ declares himself equal to the Father in power, will, and nature (Io. 5:17-27; 16:15; 10:30). His hearers interpreted Christ’s thought in this way, whether they were friends such as Peter (Mt. 16:16), or enemies such as the members of the Sanhedrin (Mt. 26:63 ff.).
If Christ is the natural Son of God, we must admit within the Godhead an act of generation, through which divine life circulates from God the Father who generates to God the Son who is generated: an eternal and necessary generation, as everything in God is eternal and necessary; of a spiritual order, because God is pure spirit; consisting in a simple origin of the Son from the Father, involving no productive action, because the Son is uncreated, unproduced. But for generation to occur, the origin must be founded on an operation which by its nature requires that the one proceeding be of the same living substance as the principle from which he proceeds. Inquiry has been made into what this operation might be, and the unanimous answer has identified it with the intellectual knowledge of God. Holy Scripture itself, presenting the S. of G. as the Word (the prologue of the Gospel of John), as the living image and splendor of the Father (Col. 1:15-19; Hebr. 1:3), leads one to think that he proceeds by way of intellection. But theological inquiry, proceeding further, asserts that the S. of G. is a son because he is the Word, because he proceeds by reason of intellectual knowledge. Indeed, in every intellection, even a created one, the word is by its nature similar to the object known, of which it is the faithful representation. In God, moreover, whose knowledge has the divine nature as its object, the Word is necessarily similar to the divine nature; and since in God there can be nothing accidental, this likeness is necessarily substantial. Therefore the Word proceeds as living God from living God, deriving his conformity with the principle from which he originates precisely from the fact that he proceeds as Word, that is, by way of intellection. Therefore the Word is the S. of G., and he is the S. of G. because he is the Word.
But every attempt of reason to sound the secret of the intimate life of God must at a certain point come to a halt in humble adoration before the depths of the mystery, whose direct knowledge is reserved for the beatific vision (v. PARADISO).