The seventh day sabbath
In Scripture, Yahuwah states: I am Yahuwah, I change not. (See Malachi 3:6.) The Sabbath was instituted at Creation, not Sinai.
Thus the heavens and the earth, and all the host of them were finished. And on the seventh day . . . [Elohim] ended His work which He had done, and He rested on the seventh day from all His work which He had done. Then . . . [Elohim] blessed the seventh day and sanctified it, because in it He rested from all His work which . . . [Elohim] created and made. (Genesis 2:1, 2, NKJV)
The Sabbath is for all people throughout all time. In the new earth, all the saved will join with the family of heaven and still keep the Sabbath holy.
"For as the new heavens and the new earth which I will make shall remain before Me," says . . . [Yahuwah], "So shall your descendants and your name remain. And it shall come to pass that from one New Moon to another, and from one Sabbath to another, all flesh shall come to worship before Me," says . . . [Yahuwah]. (Isaiah 66:22-23)
This is a fascinating passage because it does more than establish the fact that the seventh-day Sabbath will be kept for all eternity. It also establishes the calendar by which the Sabbath will be calculated! New Moon days are not an integral part of the solar Gregorian calendar's format, and they certainly are not worship days.
Knowledge of the true Sabbath and the ancient calendar instituted at Creation was lost during long years of apostasy and rebellion against Heaven. When precious truth is not valued, it is removed. Yahuwah Himself stated that He would cause the memory of the true Sabbath to be forgotten for a time: "I will also cause all her mirth to cease, her feast days, her New Moons, her Sabbaths - all her appointed feasts." (Hosea 2:11, NKJV)
The work of the final generation is to restore to its original place of honor the true Sabbath. Isaiah 58 is a prediction of the Sabbath restored:
Those from among you shall build the old waste places; you shall raise up the foundations of many generations; and you shall be called the Repairer of the Breach, the Restorer of Streets to dwell In. If you turn away your foot from the Sabbath, from doing your pleasure on My holy day, and call the Sabbath a delight, the holy day of . . . [Yahuwah] honorable, and shall honor Him . . . . (Isaiah 58:12-14, NKJV)
Seventh Day Sabbath
The Sabbath contains the seal of Yahuwah, because it is the only commandment of all the ten that contains both the name and the title of the Lawgiver: "Remember the Sabbath day, to keep it holy. Six days you shall labor and do all your work, but the seventh day is the Sabbath of . . . [Yahuwah your Elohim]." (Exodus 20:8-10a, NKJV)
The Sabbath, therefore, is the sign of loyalty which distinguishes those who serve Yahuwah from those who do not. All who love their Creator and wish to pledge their allegiance to Him, will worship on the day He sanctified and set apart: the seventh-day Sabbath on His luni-solar calendar.