Ezekiel 20:12, "Moreover, I also gave them My Sabbaths, to be a sign between Me and them, that they might know that I am Yahweh Who sanctifies them."
*Sign is Word #226, Hebrew Dictionary, Strong's Exhaustive Concordance, meaning mark, token, sign, consent, flag, evidence of consent.
Exodus 31:13-17, "Speak also to the children of Israyl, saying; Surely My Sabbaths you shall keep, for they are a sign between Me and you throughout your generations, that you may know that I am Yahweh Who sanctifies you, and makes you holy"....16-17, "Therefore the children of Israyl shall keep the Sabbath, to observe the Sabbath throughout their generations as a perpetual covenant. It is a sign between Me and the children of Israyl forever, for in six days Yahweh made the heavens and the earth, and on the Seventh Day He rested and was refreshed."
Revelation 14:9-11, "And the third malak followed them, saying with a loud voice: If any man worships the beast and his likeness, and receives his mark in his forehead or upon his hand, The same will drink of the wine of the wrath of Yahweh...........And they have no Sabbath night and day, who worship the beast and his likeness..."
This "sign" is your actions (right hand) which represents strength, what you do with your ability/life and memorial between your eyes Exodus 13:9, that explains the mark of Yahweh says: "memorial between your eyes," what do we remember with that is between our eyes? Our brain, or our thoughts and beliefs.
If you think the Sabbath is only for the Hebrew people and/or gentiles were grafted in during the NT you are Scriptually wrong:
Isayah 56:1-7, "This is what Yahweh says: Keep the judgments, and do justly; for My salvation is near, soon, to come, and My righteousness to be revealed. Blessed is the man who does this, and the son of man who lays hold on it; who keeps the Sabbaths without polluting; defiling, them; and keeps his hand from doing dany evil. Do not let the son of the Gentile, who has joined himself to Yahweh, speak, saying; Yahweh has utterly separated me from His people. Nor let the eunuch say; Behold, I am a dry tree. For this is what Yahweh says: To the eunuchs who keep My Sabbaths, and choose those things which eplease Me, and hold fast to My covenant: I will give to them, in My House, even within My walls, a place and a Name equal to that of sons and of daughters; I will give them the Name of The Everlasting: YAHWEH; which will not be cut off. Also the sons of the Gentile who join themselves to Yahweh, to serve Him, and to love the Name of Yahweh, to be His servants--everyone who keeps the Sabbaths without polluting; defiling, them and who holds fast to My covenant--I will bring them to My holy mountain, and make them joyful in My House of prayer..."