Mitch Chase notes that Gabriel is mentioned in just two books of the Bible: Daniel 8:16; 9:21 and Luke 1:19,26.

In the Daniel passages, Gabriel makes known events that were to occur in the distant future.

In the Luke passages, Gabriel makes known near-future events.  A son is to be born to Zechariah and also to Mary.

There are a number of points of comparison.  Looking first at Daniel and Zechariah:

• The Jerusalem temple.  In Dan 8:11-14, Daniel learned that something would happen to the temple. 

‘It is not only Christians, Jews and Muslims who believe in angels. Pagans have believed in them as well. Aristotle, for example, argued that there are immaterial beings responsible for the motion of the heavens (see Metaphysics 12:8), and Plotinus said that there are “guardian spirits” (see Enneads 3:4). Why has it seemed to so many, whatever their religious convictions (or lack of them), that the class of intelligent beings is not exhausted by us humans: that there ought to exist intelligences “other” and “higher” than our own?…

It was the joy of the angels of heaven to be subject and serviceable unto Jesus Christ.

(i.) Before the incarnation of Christ, an angel instructed Daniel concerning the Messiah, and how long it should be before his coming. (Dan. 9:24, 25.)

(ii.) When the fulness of time was come, an angel comes to the blessed virgin, and said, “Fear not, Mary: for thou hast found favour with God. And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name Jesus.”…

Angels are:-

A. ttendants of Christ (2 Thess. 1:7), their exalted Head (Eph. 1:21; 22; Col. 2:10)
B. ringers of good tidings concerning our salvation (see on Luke 2:14; 24:4; Acts 1:11; 1 Tim. 3:16)
C. horisters of heaven (Luke 15:10; 1 Cor. 13:1; Rev. 5:11, 12)
D. efenders of God’s children (Ps. 34:8; 91:11; Dan. 6:22; 10:10, 13, 20; Matt. 18:10; Acts 5:19; 2 Thess. 1:7–10; Rev. 12:7), though the latter outrank them and will judge them (1 Cor.…