The name “Sabbath” is derived from a Hebrew word meaning “to break off” or “to desist.” . . .
Observance of the Sabbath was made one of the Ten Commandments received by Moses at Mount Sinai . . .
But the Pentateuch, the first five books of the Bible, reached its final written form only during the Babylonian Exile, and it was not till then, perhaps, that the Sabbath received its present significance. There are, after all, but few and inconsiderable mentions of the Sabbath in the historical books dealing with the period before the Exile. It is not mentioned in the Psalms, in the Proverbs, or in the Book of Job. It is not mentioned in Deuternomy, except for its listing in the Ten Commandments.
There is speculation that the Sabbath originated among the Babylonians as a full moon festival. The Babylonians called the fifteenth day of the month “sappatu,” and in a lunar month that begins with the new moon the fifteenth day is the full moon.
The possibility that the Sabbath was a full moon festival complementary to the well-known new moon festival might be argued from various Biblical verses dated from before the Exile, verses in which the new moon and Sabbath are mentioned together in complementary fashion.
Thus, when a woman wished to go to the wonder-working prophet Elisha after her son had died of sunstroke, her husband said to her:
2 Kings 4:23. . . . Wherefore wilt thou go to him to day? it is neither new moon, nor sabbath.
The prophet Hosea quotes God as threatening Israel:
Hosea 2:11. I will cause all her mirths to cease, her feast days, her new moons, her sabbaths . . .
And Amos, characterizing the greediness of the merchants, eager to make unfair profits with false weights, pictures them sarcastically, with the parallelism characteristic of Hebrew poetry:
Amos 8:5. . . . When will the new moon be gone, that we may sell corn? and the sabbath, that we may set forth wheat . . .
It may be that the Sabbath became more than just another lunar festival during the Exile, when the priests and scribes sought for ways to mark of Jewish thinking and keep Judaism alive. They would want to prevent the assimilation that had caused the men of the Northern Kingdom of Israel to disappear in the course of their Assyrian exile.
Ezekiel (“the father of Judaism”) may have made the significant contribution of making observance of the Sabbath part of the fundamental contract between God and Israel, for Ezekiel quotes God as saying:
Ezekiel 20:12. Moreover also I gave them my sabbaths, to be a sign between me and them . . .