Deuteronomy 17:3
3 And hath gone and served other gods, and worshipped them, either the sun, or moon, or any of the host of heaven, which I have not commanded
Ezekiel 20:12
12 Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am the LORD that sanctify them
Deuteronomy 6:8
8 And thou shalt bind them for a sign upon thine hand, and they shall be as frontlets between thine eyes
Nehemiah 10:31