'Sworn' in the Bible

May God do so to Abner, and more also, if I do not do for David just as the Lord has sworn to him,

So the king called the Gibeonites and spoke to them (now the Gibeonites were not of the sons (descendants) of Israel but of the remnant (survivors) of the Amorites. The Israelites had sworn [an oath] to [spare] them, but Saul in his zeal for the sons of Israel and Judah had sought to strike down the Gibeonites).