4th Sunday of Advent, Luke 1:26-38
The angel Gabriel was sent from God to a town of Galilee called Nazareth, to a virgin betrothed to a man named Joseph, of the house of David, and the virgin’s name was Mary.
Familiar as we are with the narrative of St. Luke’s Gospel, we are tempted to take it for granted that God sent the archangel Gabriel to announce the joyful news of the Incarnation to the Most Blessed Virgin Mary.
Yet, of course, it did not need to have happened that way. God could have forgone the Annunciation all together. Or one of the Persons of the Trinity could have appeared to Mary rather than sending an angel. Further, even granting that God chose to send an angel – he could have sent a seraphim rather than an archangel, or he could have sent Michael rather than Gabriel.
Why then did God choose to send an archangel? And why did he send Gabriel?
Why it was fitting for God to send an archangel
It was right that God should announce to the Blessed Virgin the plan of salvation so that she might fully conform her will to the work which was to be effected in her. Indeed, though the Almighty did not have any absolute need of the Virgin Mary, it was fitting that (in choosing her) he should allow her to participate in the Incarnation through her obedient “yes”, her perfect fiat (let it be). And this is why our Lord announced the Incarnation to Mary in the first place, so that she would know the mystery before it was brought about, in order that she might be both a truly obedient handmaid (freely co-operating with God’s plan) and also a more perfect witness to the power of God.
Now, since the Lord desired to reveal the Incarnation to Mary before overshadowing her, it was fitting that this revelation should be announced by an angel, rather than by God himself – and this on three accounts (as St. Thomas says, ST III, q.30, a.2).
First, God sent an angel to Mary in order that the general order established by God, according to which the Divine things are brought to men by means of the angels, might be maintained. Throughout the Scriptures, God willed that the greatest events be revealed through the medium of angels; and so too was the Incarnation revealed in this way.
Second, as the redemption was brought about in such a manner as to show that the fall had been overcome in Christ, it was fitting that the same instrument which brought about the first sin should likewise announce man’s redemption. But the fallen angel Satan had first tempted Eve to eat of the tree, therefore it was fitting that an archangel be sent to direct Mary’s heart and mind to the mystery of man’s redemption.
Thirdly, as the angels are signs of purity – since, in their angelic nature, they know no lust and, by grace, are wholly free from any stain of sin – it was fitting that an angel announce this mystery to the Immaculate Virgin Mary. Indeed, she is more pure even than the angels; her virginal purity caused the angels to exclaim to one another, Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terrible as an army set in array? (Song of Solomon 6:9)
Finally, it was right that God should send an archangel rather than one of the seraphim, even though the seraphim are higher than the archangels, because the seraphim do not minister directly to men but rather the archangels are those sent to bring the most important messages. And, although there is room for debate within the tradition as to whether the archangels are among the lower choirs of angels, we recall that St. Thomas is called the “Angelic Doctor” on account of his wisdom in writing on the angels, and he tells us that the archangels are lower and that Gabriel was much lower than the seraphim while at the same time being among the greatest of those angels who are sent with messages to men. Thus, it is best to follow the Church in trusting St. Thomas’ wisdom in this matter (especially since, the Angel of the Schools [i.e. the same St. Thomas] bases his own theory on the teachings of St. Dionysius the Areopagite and also of St. Gregory the Great).
Gabriel’s prophetic proclamation in the Old Testament
Granting that God chose to send an angel and even one of the archangels, it is not yet clear why he would choose to send Gabriel rather than Raphael or Michael or another of the archangels. Considering Gabriel’s role in the Old Testament, we will gain some insight.
Gabriel has a prominent role in the book of Daniel, where he is seen to direct and oversee the wars of men. He appears at least in Daniel 8 and 9, and probably also in chapter 10 (though there is some uncertainty, since he does not explicitly state his name there).
In Daniel 9:21-25, the archangel Gabriel gives a most wondrous prophecy of the coming of the Christ. Consider the words of Scripture:
 As I was yet speaking in prayer, behold the man Gabriel, whom I had seen in the vision at the beginning, flying swiftly touched me at the time of the evening sacrifice.  And he instructed me, and spoke to me, and said: O Daniel, I am now come forth to teach thee, and that thou mightest understand.  From the beginning of thy prayers the word came forth: and I am come to shew it to thee, because thou art a man of desires: therefore do thou mark the word, and understand the vision.  Seventy weeks are shortened upon thy people, and upon thy holy city, that transgression may be finished, and sin may have an end, and iniquity may be abolished; and everlasting justice may be brought; and vision and prophecy may be fulfilled; and the saint of saints may be anointed.  Know thou therefore, and take notice: that from the going forth of the word, to build up Jerusalem again, unto Christ the prince, there shall be seven weeks, and sixty-two weeks: and the street shall be built again, and the walls in straitness of times.
Gabriel speaks of the “seventy weeks” and of the “sixty-nine weeks”, which refer to “weeks of years”, that is four-hundred ninety and four-hundred eighty-three years, respectively – (“weeks of years”, as in Leviticus 25,8: Thou shalt also number to thee seven weeks of years, that is to say, seven times seven, which together make forty-nine years). On this passage from Daniel, the commentary in the Douay-Rheims Bible states:
Seventy weeks: Viz., of years, (or seventy times seven, that is, 490 years,) are shortened; that is, fixed and determined, so that the time shall be no longer.
From the going forth of the word: That is, from the twentieth year of king Artaxerxes, when by his commandment Nehemias rebuilt the walls of Jerusalem, 2 Esd. 2. From which time, according to the best chronology, there were just sixty-nine weeks of years, that is, 483 years to the baptism of Christ, when he first began to preach and execute the office of Messias.-- Ibid.
Whether we accept the precision of the chronology, it is quite clear that the archangel Gabriel gives one of the most precise prophecies of the coming of the Christ. Hence, it was fitting that he who had announced the mystery of old, should announce the same when the fullness of time had come.
“The Power of God” and “The Man of God”
Finally, to understand why it was that God chose Gabriel both in the Old Testament and in the fullness of time to announce to men the good news of the Incarnation, we consider the meaning of his name and the particular role which he has among the other archangels. We look to the great Fr. Cornelius a’ Lapide:
“S. Jerome remarks on Daniel viii. that there are three angels, Michael, Raphael, and Gabriel, who are especially mentioned in Scripture; of whom Michael presides over the prayers and offerings of the faithful and is therefore called Michael (that is, ‘who is like God’); for it is the prerogative of God alone to hear the prayers of penitents: while Raphael presides over the healing of men’s bodies, and he therefore restored sight to Tobias when he was blind; whence he is called Raphael (that is ‘the Healer or the Healing, of God’); and thirdly Gabriel (or ‘the strength of God’) presides over the conflicts and wars of the faithful (as is clear from Dan. xii. &c.). Wherefore he is sent to announce the birth of Christ, who was to carry on a most severe war against Lucifer, and the rest of the demons and impious men.
“Again Gabriel in Hebrew means ‘man of God’; the meaning of which is that God will be incarnate, and will be a child as to nature and age; but yet He will also be a man, because from the first instant of His conception His soul will be full of all knowledge, grace, and strength, according to the saying of Jer. xxxi. 22, a woman shall compass a man.”