The Advent Truth.
The problem is people confuse the COVENANT made at Sinai with the EXISTENCE of God’s law.

Deuteronomy 5:2-3 says the covenant at Horeb was made with Israel. True. But does that mean murder, adultery, idolatry, and lying didn’t exist before Sinai too? Of course not.

The Sabbath existed long before there was ever a Jew.

Genesis 2:2-3 says God rested, blessed, and sanctified the seventh day at CREATION. That’s before Abraham, before Moses, before Sinai, and even before sin entered the world.

And here’s what many miss:

Exodus 16 shows Israel already being tested on the Sabbath BEFORE they reached Mount Sinai and before the Ten Commandments were spoken in Exodus 20.

God literally rebuked them:
“How long refuse ye to keep my commandments and my laws?” (Exodus 16:28)

You cannot break a commandment that doesn’t exist.

And Abraham himself?
Genesis 26:5 says Abraham “obeyed my voice, and kept my charge, my commandments, my statutes, and my laws.”

So no — the Sabbath was not invented at Sinai.

Sinai was a restoration and codification of principles humanity had largely forgotten during centuries of Egyptian bondage.

That’s why Exodus 20 says:
“REMEMBER the sabbath day…”

You don’t “remember” something brand new.

Jesus also destroyed the idea that the Sabbath was only for Jews:
“The sabbath was made for MAN…” (Mark 2:27)

Not merely for Israel.
For mankind.

And Isaiah says Sabbath keeping continues even in the New Earth:
Isaiah 66:22-23

The Sabbath began in Eden, was reaffirmed at Sinai, honored by Christ, practiced by the apostles, and will exist in eternity.

The real issue isn’t whether the Sabbath existed before Sinai.

The real issue is whether people are willing to accept what Scripture plainly says.