'Sign' in the Bible

the censers of these sinners who have forfeited their life; and they shall make them into broad plates for the covering of the altar; for they presented them before Jehovah, therefore they are hallowed; and they shall be a sign unto the children of Israel.

And the earth opened its mouth, and swallowed them up together with Korah, when that band died, when the fire devoured the two hundred and fifty men; and they became a sign.