Malachi 4:4 Remember ye the law of Moses my servant, which I
commanded unto him in Horeb for all Israel, [with] the statutes
and judgments.

He gave an original law
today we have a breached law in Exodus 20:8

Malachi 4:5 Behold, I will send you Elijah the prophet before the
coming of the great and dreadful day of Y'hovah:

His work in part is to "repair the breach"

Isaiah 58:12 And they that shall be of thee shall build the old
waste places: thou shalt raise up the foundations of many
generations; and thou shalt be called; The repairer of the breach,
The restorer of paths to dwell in.

"Raise up the foundations of many generations" for most of earth's history, the moon has been the calendar, and the only calendar of Scripture, of The Book of Jashur, of The Book of Enoch.

Malachi 4:6 And he shall turn the heart of the fathers to the
children, and the heart of the children to their fathers, lest
I come and smite the earth with a curse.

YHVH will come and perform Ezekiel 9 to the SDA's who reject His
Law, and who continue to transgress with the "breached" fourth
commandment.

Prophets and Kings page 678

In the time of the end every divine institution is to be restored.
The breach made in the law at the time the Sabbath was
changed by man, is to be repaired.