Is it significant that God sent Gabriel to both Joseph and Mary rather than Michael or some other angel?
Actually, the Bible does not specify that the angel who spoke to Joseph in a dream was Gabriel. All we know for sure is that it was “an angel of the Lord” (Matt. 1:20ff). His message to Joseph is strikingly similar, however, to Gabriel’s message addressed to Mary (Lk. 1:26ff); and Luke 1:19 tells us that it was Gabriel who appeared to Zechariah with the news that Elizabeth was to have a child in her old age. So it is certainly likely that the angel Joseph encountered was Gabriel as well.
The only other times in Scripture that Gabriel is mentioned by name is in the book of Daniel, chapters 8 and 9, where Daniel receives from the angel an interpretation of his vision of the end times. When we compare his activities with that of Michael, another angel of the Lord, some striking differences between them emerge.
In each angel encounter with Gabriel, he is quite talkative—not in a prattling way, but he does have much to say as he dialogues with humans. In contrast, the archangel Michael has virtually no direct communication with human beings, but rather acts as a guardian and protector for the prophet Daniel (Dan. 10:13) and for the people of Israel as a whole (Dan. 12:1; Rev. 12:7). In fact, the only reference we have to Michael saying anything at all is from the book of Jude, where “the archangel Michael, when he was disputing with the devil about the body of Moses, did not dare to bring a slanderous accusation against him, but said, ‘The Lord rebuke you!’” (9).
From the evidence available in Scripture, it seems evident that God’s appointed role, at least in part, for Gabriel is to serve as His principal messenger to key people in the outworking of His plan of salvation throughout history. Michael’s principal role is apparently that of Israel’s protector from those who would derail God’s chosen people from their appointed place in God’s plan of salvation.
In either case, these glorious beings represent a vast host of heavenly beings (Heb. 12:12), all of whom are “ministering spirits sent to serve those who will inherit salvation” (Heb. 1:4). As beautiful, powerful and other-worldly as the angels are, “it is not to angels that he has subjected the world to come…” (Heb. 2:5). “But we see Jesus, who was made a little lower than the angels, now crowned with glory and honor because he suffered death, so that by the grace of God he might taste death for everyone” (Heb. 2:9).