One is the Son, both before the incarnation and after the incarnation. The same (Son) is both man and God, both these together as though one; and the God the Word is not one person, and the man Jesus another person, but the same who subsisted as Son before was made one with flesh by Mary, so constituting Himself a perfect, and holy, and sinless man, and using that economical position for the renewal of mankind and the salvation of all the world. God the Father, being Himself the perfect Person, has thus the perfect Word begotten of Him truly, not as a word that is spoken, nor yet again as a son by adoption, in the sense in which angels and men are called sons of God, but as a Son who is in nature God.
And there is also the perfect Holy Spirit supplied of God through the Son to the sons of adoption, living and life-giving, holy and imparting holiness to those who partake of Him—not like an unsubstantial breath breathed into them by man, but as the living Breath proceeding from God. Wherefore the Trinity is to be adored, to be glorified, to be honoured, and to be reverenced; the Father being apprehended in the Son even as the Son is of Him, and the Son being glorified in the Father, inasmuch as He is of the Father, and being manifested in the Holy Spirit to the sanctified.
Source: A Sectional Confession of Faith (New Advent)