'Sign' in the Bible

Put up a flag for a sign to Zion: go in flight so that you may be safe, waiting no longer: for I will send evil from the north, and a great destruction.

O ye children of Benjamin, gather yourselves to flee out of the midst of Jerusalem, and blow the trumpet in Tekoa, and set up a sign of fire in Bethhaccerem: for evil appeareth out of the north, and great destruction.

The sin of Judah is recorded with a pen of iron, and with the sharp point of a jewel it is cut on their hearts of stone, and on the horns of their altars for a sign to them:

People will buy fields for money, sign deeds, seal them, and call witnesses in the land of Benjamin, in the areas around Jerusalem, in the towns of Judah, the towns of the hill country, the towns of the Shephelah, and the towns of the Negev, for I'll restore their fortunes,' declares the LORD."

And this shall be a sign unto you, saith the LORD, that I will punish you in this place, that ye may know that my words shall surely stand against you for evil: