Matthew Poole and continuators on Luke 1:35

35 And the angel answered and said unto her, The holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that Holy thing which shall be born of thee, shall be called theSon of God.

The Holy Ghost, (who is also called here the Power of the Highest,) shall come upon thee; it is a Phrase which signifieth a special and peculiar influence of the holy Spirit; thus we read of the Prophets, That the Spirit of the Lord came upon them, 2 Chron. 20.14, &c. which argued a special Influence of the Holy Spirit on them, efficacious, so as it put them upon a present Prophecying. There is a common influence of God upon the forming of all Children in the Womb, Iob 10.8. Psal. 139.5. But this Phrase denoteth, an extraordinary special influence of the Spirit, changing the order and course of Nature, and giving a Power to the Blood of the Virgin by him sanctified, to coagulate alone to the forming of a body of a Child; this is more Mysteriously yet exprest, by the next term over shadow thee, which I take to be a modest Phrase, signifying only a supply of Mans act, by a Divine creating Power▪ in a most miraculous manner. Therefore also that holy thing, which shall be born of thee, shall be called the Son of God, as Adam was called the Son of God, Chap. 3. God (by his creating Power) supplying as to him the place of Fathe[illegible: 1 letter] and Mother, and to Christ, supplying the place of the Father, tho not of the Mother, for (saith the Angel) he shall be born of thee. But yet that Mass of Flesh, shall be an holy thing, because tho born of thee, and Flesh of thy Flesh, yet of thy Flesh first sanctified, by the Holy Ghost coming upon and over-shadowing of thee. He shall be called so, not that he was not so by eternal Generation, (of which the Angel here speaks not,) but the Word the eternal Son of God, which was in the begining, being thus made Flesh, and personally united to thy Flesh, the whole Person shall be called, The Son of God.