'Witness' in the Bible

He said to them, "The Lord is witness against you, and his chosen king is witness this day, that you have not found any reason to accuse me." They said, "He is witness!"

Jonathan said to David, "The Lord God of Israel is my witness. I will feel out my father about this time the day after tomorrow. If he is favorably inclined toward David, will I not then send word to you and let you know?

With regard to the matter that you and I discussed, the Lord is the witness between us forever!"