'Sign' in the Bible

And God said, “Certainly I will be with you, and this shall be the sign to you that it is I who have sent you: when you have brought the people out of Egypt, you shall serve and worship God at this mountain.”

“If they will not believe you or pay attention to the evidence of the first sign, they may believe the evidence of the second sign.

I will put a division (distinction) between My people and your people. By tomorrow this sign shall be in evidence.”’”

The blood shall be a sign for you on [the doorposts of] the houses where you live; when I see the blood I shall pass over you, and no affliction shall happen to you to destroy you when I strike the land of Egypt.

It shall serve as a sign to you on your hand (arm), and as a reminder on your forehead, so that the instruction (law) of the Lord may be in your mouth; for with a strong and powerful hand the Lord brought you out of Egypt.

“But as for you, say to the Israelites, ‘You shall most certainly observe My Sabbaths, for it is a sign between Me and you throughout your generations, so that you may know [without any doubt] and acknowledge that I am the Lord who sanctifies you and sets you apart [for Myself].

It is a sign between Me and the Israelites forever; for in six days the Lord made the heavens and the earth, and on the seventh day He ceased and was refreshed.”