“The keys of the kingdom… bind and loose”
I will give you the keys of the kingdom of heaven. Whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven. (Matthew 16:19 BSB)
What it sounds like today
Mystical powers: Peter at the pearly gates with a keyring.
The cultural key
Both images were current legal idiom. 'Bind' and 'loose' were the rabbinic terms for authoritative rulings: to bind is to forbid, to loose is to permit: the everyday vocabulary of teachers deciding how Torah applies. The key was the steward's emblem: Isaiah 22:22 lays 'the key of the house of David' on Eliakim's shoulder, the palace administrator who opens and shuts in the king's name. Jesus accuses the scribes of the negative image: they 'shut the kingdom of heaven in people's faces' (Matthew 23:13).
Recovered meaning
Peter is made chief steward, not gatekeeper of the afterlife: authorized to open what the current teachers have locked, and to make rulings, forbid and permit, that heaven stands behind. The same binding/loosing authority extends to the community in Matthew 18:18.