'Confirm' in the Bible

in order to confirm the oath which I swore to your forefathers, to give them a land flowing with milk and honey, as it is this day.”’” Then I said, “Amen, O Lord.”

and the prophet Jeremiah said, “Amen! May the Lord do so; may the Lord confirm your words which you have prophesied to bring back the vessels of the Lord’s house and all the exiles, from Babylon to this place.

thus says the Lord of hosts, the God of Israel, as follows: ‘As for you and your wives, you have spoken with your mouths and fulfilled it with your hands, saying, “We will certainly perform our vows that we have vowed, to burn sacrifices to the queen of heaven and pour out drink offerings to her.” Go ahead and confirm your vows, and certainly perform your vows!’