'Oath' in the Bible

The Lord said,“I have made a covenant with My chosen one;I have sworn an oath to David My servant:

Once and for allI have sworn an oath by My holiness;I will not lie to David.

So He raised His hand against them with an oaththat He would make them fall in the desert

The Lord has sworn an oath and will not take it back:“Forever, You are a priestlike Melchizedek.”

and how he swore an oath to the Lord,making a vow to the Mighty One of Jacob:

The Lord swore an oath to David,a promise He will not abandon:“I will set one of your descendantson your throne.