The Sabbath is a perpetual sign between YAHUWAH the Creator, and His chosen people: 
📖 Exodus 31:16–17: “Wherefore the children of Yisra’ĕl shall guard the Sabbath, to observe the Sabbath throughout their generations as an everlasting covenant. It is a sign between Me and the children of Yisra’ĕl forever…”

Those who do not honor the Sabbath have no covenantal bond with YHWH:
📖 Ezekiel 20:12–13: “Moreover also I gave them My Sabbaths, to be a sign between Me and them, that they might know that I am YAHUWAH who set them apart. But the house of Yisra’ĕl rebelled against Me…”

Those who do not call exclusively upon His true Name, nor bear it upon their foreheads, do not belong to YAHUWAH, neither shall enter into His Kingdom: 
📖 Joel 2:32: “And it shall come to pass, that whosoever shall call on the Name of YAHUWAH shall be delivered…”
📖 Revelation 14:1: “...having His Father's Name written in their foreheads.”
📖 Malachi 3:16–17: “...a book of remembrance was written before Him for them that feared YAHUWAH, and that thought upon His Name.”

YAHUWAH's commandment is His Covenant with His chosen people: 

📖 MatthiYahu 7:21–23: “Not everyone who says to Me, ‘Master, Master,’ shall enter into the reign of the heavens, but he who does the desire of My Father in the heavens.”

📖 Revelation 22:14: “Blessed are those doing His commandments, so that the authority shall be theirs unto the tree of life, and to enter through the gates into the city.”