Uhhh... I'm right here reading it right now. I could just tell you.
Why, you know what, I think I will!
Gabriel is one of the seven "archangels" of Judaism.
Of the seven archangels, only two are really accepted by modern christianity- Michael and Gabriel. (Sometimes Raphael.)
The archangel Michael was the leader of the hosts of heaven in casting out the devil. He's basically the most noble and brightest angel below Christ himself.
Archangel Gabriel is second only to Michael- in fact, Gabriel worked as the messenger of the lord (angel meaning messenger, and arch meaning chief), so when someone needed to break the news to Zacharias that he was a 75 year old daddy, Gabriel met him in the temple and told him.
Gabriel also the angel who appeared to Joseph in a dream to tell him to stay with Mary, and appeared to Mary herself to tell her that she was going to have a virgin birth and be the mother of the Son of God.
Gabriel is also purported by some religions (mine) to have been Noah during his mortal life, and served as a head of a dispensation of the gospel (Adam, Enoch, Noah, Abraham, Moses, Christ (Peter), Smith).
But yeah. That's why no one asks me stuff like that.
-kv