And the children of Israel ate manna forty years, until they came to an inhabited land; they ate manna until they came to the border of the land of Canaan. Exodus 16:35, NKJV. BLJ 138.1
Every week during their long sojourn in the wilderness the Israelites witnessed a threefold miracle, designed to impress their minds with the sacredness of the Sabbath: a double quantity of manna fell on the sixth day, none on the seventh, and the portion needed for the Sabbath was preserved sweet and pure, when if any were kept over at any other time it became unfit for use. BLJ 138.2
In the circumstances connected with the giving of the manna, we have conclusive evidence that the Sabbath was not instituted, as many claim, when the law was given at Sinai. Before the Israelites came to Sinai they understood the Sabbath to be obligatory upon them. In being obliged to gather every Friday a double portion of manna in preparation for the Sabbath, when none would fall, the sacred nature of the day of rest was continually impressed upon them. And when some of the people went out on the Sabbath to gather manna, the Lord asked, “How long refuse ye to keep my commandments and my laws?” BLJ 138.3
“The children of Israel did eat manna forty years, until they came to a land inhabited; they did eat manna, until they came unto the borders of the land of Canaan.” For forty years they were daily reminded by this miraculous provision, of God's unfailing care and tender love. In the words of the psalmist, God gave them “of the corn of heaven. Man did eat angels’ food” (Psalm 78:24, 25)—that is, food provided for them by the angels. Sustained by “the corn of heaven,” they were daily taught that, having God's promise, they were as secure from want as if surrounded by fields of waving grain on the fertile plains of Canaan.—Patriarchs and Prophets, 296, 297. BLJ 138.4