Saul said to the Lord, the God of Israel, "Lord, why have you not answered me today? Lord, God of Israel, answer me by the sacred stones. If the guilt is Jonathan's or mine, answer by the Urim; but if it belongs to your people Israel, answer by the Thummim." The answer indicated Jonathan and Saul; and the people were cleared. 1
References for 1 Samuel 14:41
14.41 Nu 27.21; 1 S 28.6.