'Oath' in the Bible

So Jephthah went with the elders of Gilead, and the people appointed him head and military commander over them. Jephthah uttered everything he had to say with the solemnity of an oath in the LORD's presence at Mizpah.

The Israelis asked themselves, "Who didn't come up in our assembly in the LORD's presence from among all of the tribes of Israel?" They had taken a solemn oath concerning those who didn't come up to meet with the LORD at Mizpah that "They will certainly be executed."

What can we do to find wives for the survivors who remain, since we've already taken an oath in the LORD's presence not to give them any of our daughters in marriage?"