'Witness' in the Bible

This will happen to them because they have done what is shameful in Israel. They have committed adultery with their neighbors' wives and have spoken lies while claiming my authority. They have spoken words that I did not command them to speak. I know what they have done. I have been a witness to it,' says the Lord."

They answered Jeremiah, "May the Lord be a true and faithful witness against us if we do not do just as the Lord sends you to tell us to do.