'Oath' in the Bible

Then in the seventh year, Jehoiada sent for the captains of hundreds of the Carians, and the armed men, and taking them into the house of the Lord, made an agreement with them, and made them take an oath in the house of the Lord, and let them see the king's son.

Then Gedaliah gave his oath to them and their men, saying, Have no fear because of the servants of the Chaldaeans; go on living in the land under the rule of the king of Babylon, and all will be well.