'Sign to You' 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.”

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.