Oath-taking was a solemn affair in the Old Testament. To take an oath was to give a sacred and unbreakable word that you would follow through on what was promised. God often swears by himself, his holiness or his great name (Genesis 22:16–18; Psalm 89:35; Jeremiah 44:26). Swearing falsely was a grave sin (Ezekiel 17:16–21; Zechariah 5:3–4; Malachi 3:5). Because of the sacred, unbreakable nature of an oath, the treaty made with the Gibeonites could not be revoked even if made under false pretences.1
18 But the people of Israel did not attack them, because the leaders of the congregation had sworn to them by the LORD, the God of Israel. Then all the congregation murmured against the leaders.