37 These are the fixed feasts of the Lord, to be kept by you as holy days of worship, for making an offering by fire to the Lord; a burned offering, a meal offering, an offering of beasts, and drink offerings; every one on its special day; 38 In addition to the Sabbaths of the Lord, and in addition to the things you give and the oaths you make and the free offerings to the Lord. 39 But on the fifteenth day of the seventh month, when you have got in all the fruits of the land, you will keep the feast of the Lord for seven days: the first day will be a Sabbath, and the eighth day the same.

Matthew Henry's Commentary on Leviticus 23:37-39

Commentary on Leviticus 23:33-44

(Read Leviticus 23:33-44)

In the feast of Tabernacles there was a remembrance of their dwelling in tents, or booths, in the wilderness, as well as their fathers dwelling in tents in Canaan; to remind them of their origin and their deliverance. Christ's tabernacling on earth in human nature, might also be prefigured. And it represents the believer's life on earth: a stranger and pilgrim here below, his home and heart are above with his Saviour. They would the more value the comforts and conveniences of their own houses, when they had been seven days dwelling in the booths. It is good for those who have ease and plenty, sometimes to learn what it is to endure hardness. The joy of harvest ought to be improved for the furtherance of our joy in God. The earth is the Lord's, and the fullness thereof; therefore whatever we have the comfort of, he must have the glory of, especially when any mercy is perfected. God appointed these feasts, "Beside the sabbaths and your free-will offerings." Calls to extraordinary services will not excuse from constant and stated ones.