'Sign' in the Bible

And thou shalt bind them for a sign upon thine hand, and they shall be as frontlets between thine eyes.

Therefore shall ye lay up these my words in your heart and in your soul, and bind them for a sign upon your hand, that they may be as frontlets between your eyes.

If there arise among you a prophet, or a dreamer of dreams, and giveth thee a sign or a wonder,

And the sign or the wonder come to pass, whereof he spake unto thee, saying, Let us go after other gods, which thou hast not known, and let us serve them;

And they shall be upon thee for a sign and for a wonder, and upon thy seed for ever.