So... it seems we agree that we might have at least one or more guardian angels.
What about their "ministry"? We've elaborated on "protection". Here's an interesting picture of an angel "ministering" to Jesus after the temptation in the wilderness:
Do they pray for us?
Encourage us?
Reveal, instruct, or teach things to us? (Like the angel that spoke to Cornelius,
Acts 10:4-6)