THE INCARNATION OF THE SON OF GOD (the third article of the Creed).
The Son of God, who is also called "the Word," became incarnate, i.e. flesh or man by the power of the Holy Ghost, being "conceived of the Holy Ghost," i. e. having no human father--St. Joseph being only His foster-father or legal father [in the eyes of the law]--, and "born of Mary the most pure Virgin." St. John (1:18) says: "The Word was made flesh and dwelt among us." When the Son of God became man, He did not cease to be God, for that would have been quite impossible, but He assumed the human nature unto His Divine Person. There are, therefore, two natures in Jesus Christ, the divine nature and the human nature, but there is only one person in Him, the person of God the Son. Jesus Christ is therefore God and Man, the Son of God and the Son of David, the true Emmanuel, i. e. God with us.
[From 'A Practical Commentary on Holy Scripture' by Bishop Knecht, D.D.]
(1899 Douay-Rheims Bible)