Each of the Great Feasts of the Church is followed by a commemoration of some holy one who figures in the events of the Feast. So, today we commemorate the Holy Archangel Gabriel, who brought the glad news of the conception of Christ to Mary, the Theotokos. The Prologue gives the following teaching:
  "The herald of the incarnation of the Son of God, he is one of the seven great angels who stand before the throne of God. He revealed to Zacharias the birth of the Forerunner, and said of himself: 'I am Gabriel that stand in the presence of God' (Lk. 1:19). His name, Gabriel, signifies 'man of God'. Speaking about the Annunciation, the holy Fathers comment that an angel with such a name was sent to signify who He was, and of what nature He was, who would be born of the most pure Virgin. He would be the Man of God, the Man-God, the strong and mighty God. Others have found that it was this same Gabriel who announced the conception of the Virgin Mary to Joachim and Anna, and that it was he who taught Moses in the wilderness to write the Book of Genesis. The holy Fathers consider that Gabriel belongs to the foremost and highest order of the heavenly powers, the seraphim, since the seraphim stand closest to God. And so he is one of the seven seraphim closest to God. The names of these seven are: Michael, Gabriel, Raphael, Uriel, Selathiel, Jegudiel and Barachiel. Some would add Jeremiel to this number. Each has his own particular service, but all are equal in honour. Why did God not send Michael? For the reason that Michael's service is the suppression of the enemies of God's truth, while Gabriel's is the annunciation of the salvation of the human race."