Q. 22. How did Christ, being the Son of God, become man?

A. Christ, the Son of God, became man, by taking to himself a true body, and a reasonable soul [a], being conceived by the power of the Holy Ghost, in the womb of the virgin Mary, and born of her [b] yet without sin [c].

[a]. Phil. 2:7; Heb. 2:14, 17

[b]. Luke 1:27, 31, 35

[c]. 2 Cor. 5:21; Heb. 4:15; 7:26; 1 John 3:5


Source https://www.apuritansmind.com/westminster-standards/shorter-catechism/