Ah, yes, the restoration of the Aaronic Priesthood, which nobody heard about until much later.
This is a section that I memorized at a camp-out that my ward organized for the commemoration of the auspicious occasion when the power to baptize was returned to the earth.
It's an odd verse, though. I get what the keys of baptism by immersion are. But what, exactly are the keys of the ministering of angels? There is no way any of us had access to something that badass-sounding as Aaronic Priesthood holders. There were no angels involved in the teachers' quorum. I'm guessing the understanding today is that the angels mentioned here aren't literal, but rather a nod to the Aaronic Priesthood's ability to perform the spiritual functions that ministering angels often perform.
But what are those spiritual functions? Should I have had the ability to step into a fiery furnace and protect God's favorites from the flames? Should I have been able to foretell the birth of an important prophet? Should I have been empowered to smite wicked rulers? Should I have become prone to sudden intervention whenever a prophet is getting a beatdown? Should I have made midnight visits to government leaders to teach them gospel doctrine? Because I can guarantee you that this kind of stuff takes place in exactly zero quorums of deacons, teachers, and priests.
And what's this deal with the sons of Levi? Is God saying that the authority to direct the work priesthood will be removed from the earth when Levite descendants resume their tribe's anciently appointed priesthood responsibilities? Why would God ever want to remove the priesthood keys in the first place, especially if we're heading into the last dispensation of time? Maybe "until the sons of Levi to offer again an offering unto the Lord in righteousness" is his scriptural way of saying "when pigs fly."
I gotta say, for being probably the shortest section in the entire Doctrine and Covenants, this verse leaves a lot of unanswered questions.