Matthew 1:18-25 The Virgin Birth Of Jesus.
It was important for Matthew to go back to Jesus’ birth in establishing his rightful lineage to David. However, if an angel had not appeared to Joseph it is certain that he would have put away, or divorced Mary, as it were (vv. 18-20 Cf. Lk. 1:27, 35; Dt. 24:1). He must have pondered deeply the thought that this boy would be conceived of the Holy Spirit. He was also given the name Jesus, because He would “save His people from their sins” (v. 21 Cf. Lk. 1:31; 2:21; Jn. 1:29). From the very beginning Jesus coming was in fulfillment of the words of the prophets, in this case the promise of Isaiah (vv. 22-23 Cf. Is. 7:14).* Then we find a very simple account of Joseph’s obedience to the word from the Lord, and he also kept her as a virgin until Jesus’ birth (vv. 24-25 Cf. Lk. 2:7, 21). The genealogy showed that Jesus was in the rightful line to be crowned as the Anointed One, and His birth, and the name of ‘Jesus’, informed the world what would be the nature of His reign.
* “This quotation is the first of a number of Old Testament references Matthew uses to show that Jesus fulfills the Old Testament (2:6, 15, 18, 23). In the entire Gospel there are twelve such formulas, and more than fifty Old Testament quotations” (NGSB p.1506).