Im writing a fantasy story right now, where in one point, God will send Gabriel down to Earth to aid MC on his battle. As the messenger of God, i thought it would make sense if i give him the ability that match his role, which is to send people to past/future Although, i put limits to his power. That power was supposed to help Gabriel proofing the "chosen ones" that God is real, by bringing them to few parts of past and future, so neither Gabriel or the person he brought there could actually interact with the past or future they visit. So they're only there as an audience, unknown to the people around them. But i want that "semi time-travel" ability to be actually useful in battles, for example, transferring the characters to the past/future before a barrage of lethal attacks hit them. Are there a better way to give Gabriel this kind of power without making it a deus ex machina for himself or the MC?
I dont think it is contrived to let Gabriel have this power. If you buy into angels then Gabriel has all his powers from God. And God can give what ever power He wants. It can seems like contrived if there is no other connection with God. I think of the film "A wonderful life" which starts with conversation between God and Moses and also you seee a lot of people praying for George Bailey.