According To Luke: An Analytical Commentary

34 Then said Mary unto the angel, How shall this be (not doubting like Zacharias, but asking for understanding), seeing I know not a man? (euphemism for virginity; confirms her purity).

35 And the angel answered and said unto her, The Holy Ghost (third Person of the Trinity) shall come upon thee (divine overshadowing; power of God initiates conception), and the power of the Highest (God Himself) shall overshadow thee (language of God’s presence — cf. Ex. 40:35; Ps. 91:1): therefore also that holy thing (‘thing’ is italicized, meaning it is not in the original Greek) which shall be born (conceived without Original sin, which seems to be traduced by the natural father) of thee shall be called the Son of God (eternally begotten, without beginning —ontologically God in the Person of the Son ).

36 And, behold, thy cousin (relative/kin; probably a cousin) Elisabeth, she hath also conceived a son in her old age (miracle in itself — sign and comfort for Mary): and this is the sixth month with her (reinforces the timeline; John was 6 months older than Jesus), who was called barren (public knowledge of her condition — now overturned).

37 For with God nothing shall be impossible (God is omnipotent—able to do all things that are consistent with His nature. He cannot lie (Titus 1:2), nor can He deny Himself (2 Tim. 2:13), meaning He cannot act contrary to His own character. But no promise or purpose of His can ever fail; what is impossible with man is never impossible with God—cf. Gen. 18:14.).