John Calvin Commentary Leviticus 23:34

"Speak unto the children of Israel, saying, On the fifteenth day of this seventh month is the feast of tabernacles for seven days unto Jehovah." — Leviticus 23:34 (ASV)

The fifteenth day of this seventh month. It is shown at the end of the chapter why God instituted the Feast of Tabernacles: namely, that the children of Israel might remember that they lived in tents in the desert, when they had no certain dwelling place but, as it were, passed a wandering life.

The Passover showed how they were marvelously rescued from immediate death by the hand of God. By this other feast day, however, God magnified the continuous and daily flow of His grace, for it would not have been enough to acknowledge His power in their actual departure and to give Him thanks for their momentary deliverance, unless they also fully reflected on the progress of their complete deliverance, which they had experienced for forty years.

Referring to this, the Prophet Zechariah, when speaking of the second redemption, commands all the nations who would be converted to the worship of God that they should go up every year to celebrate this day (Zechariah 14:16). And why this feast rather than the other festivals? Because their return from Babylon—a long and difficult journey, endangered by the violent assaults of enemies—would be as memorable as the passage of the people from Egypt into the Promised Land.

From this we gather that, though the ceremony is now abolished, its significance still exists in spirit and in truth, so that the incomparable power and mercy of God should be constantly kept before our eyes, since He has delivered us from darkness and from the deep abyss of death, and has translated us into the heavenly life.

But it was fitting that the ancient people, in their limited understanding, should be trained in this way. All, from youth to old age, by going out from their homes, were to be brought, so to speak, into the actual historical circumstances. In that spectacle, they were to perceive what otherwise would never have sufficiently penetrated their minds. At the same time, they were instructed for the future that even in the land of Canaan they were to be sojourners, since this is the condition prescribed for all the pious and the children of God: that they should be strangers on earth if they desire to be inheritors of heaven.

Especially, however, God intended to stir them to gratitude, so that they might more highly value their peaceful occupation of the Promised Land and the comfort of their houses, when they remembered that they were brought there by His hand out of the desert and from the most wretched destitution of all things.