'Sign' in the Bible

As for the censers of these men who have sinned at the cost of their lives, let them be made into hammered sheets for a plating of the altar, since they did present them before the Lord and they are holy; and they shall be for a sign to the sons of Israel.”

But the Lord said to Moses, “Put back the rod of Aaron before the testimony to be kept as a sign against the rebels, that you may put an end to their grumblings against Me, so that they will not die.”