Christmas
The relation between Jesus’ divine sonship and the Holy Spirit is evident at two other key junctures in the story of Jesus, viz., his baptism (3:16–17) and his resurrection (Rom 1:4).
Emmanuel, μεθʼ ἡμῶν ὁ θεός, “God with us” (LXX Isa 8:8, 10). Indeed this is not a personal name but rather a name that is descriptive of the task this person will perform. Bringing the presence of God to man, he brings the promised salvation—which, as Matthew has already explained, is also the meaning of the name Jesus (v 21b). “They” who will call him Emmanuel are those who understand and accept the work he has come to do. Matthew probably intends the words of Jesus at the end of his Gospel—“Behold I am with you always, until the end of the age” (28:20)—to correspond to the meaning of Emmanuel. Jesus is God, among his people to accomplish their salvation (see Fenton, “Matthew,” 80–82).
The situation described in these verses is Joseph’s legal engagement to Mary. If typical Jewish custom were followed, she may well have been still a young teenager. Joseph may have been considerably older. Engagement in ancient Judaism was legally binding and required divorce if it were to be broken, but sexual relations and living together under one roof were not permitted until after the marriage ceremony. Joseph could therefore be spoken of already as Mary’s husband, but Matthew emphasizes this was “before they came together.”