'Take an Oath' in the Bible

Then they said, We will give them back, and take nothing for them; we will do as you say. Then I sent for the priests and made them take an oath that they would keep this agreement.

And I took up the cause against them, cursing them and giving blows to some of them and pulling out their hair; and I made them take an oath by God, saying, You are not to give your daughters to their sons or take their daughters for your sons or for yourselves.