Luke 1:30-33
Gabriel had a HUGE message to give Mary. While it didn't directly affect him, as in he would not be receiving salvation himself, it was a message that literally changed the world!
Remember, the angels were messengers and they say what God tells them to. I’ve often wondered why the verbiage sounds like Jesus was coming to over-throw the reigning King of Israel. The wording sounds like it, which is why Herod freaked out and started killing babies. Jesus wasn't planning on reigning physically and staying here forever. (Spoiler alert, that happens later.)
Jesus reigns over everything in Heaven and earth, just not the way they thought. Since they were oppressed by Rome, they wanted freedom, so you will assume anything when you are in a position like that.
I'm glad Gabriel is obedient and follows God’s commands. I’m sure he is still around serving God and Jesus.