| Gill's Exposition of the Entire Bible Thou shalt observe the feast of tabernacles seven days,.... Which began on the fifteenth day of Tisri, or September; see Leviticus 23:34, &c. after that thou hast gathered in thy corn and thy wine; and therefore sometimes called the feast of ingathering, Exodus 23:16, barley harvest began at the passover, and wheat harvest at Pentecost; and before the feast of tabernacles began, the vintage and the gathering of the olives were over, as well as all other summer fruits were got in.
Keil and Delitzsch Biblical Commentary on the Old TestamentIn connection with the Feast of Tabernacles also, he simply enforces the observance of it at the central sanctuary, and exhorts the people to rejoice at this festival, and not only to allow their sons and daughters to participate in this joy, but also the man-servant and maid-servant, and the portionless Levites, strangers, widows, and orphans. After what had already been stated, Moses did not consider it necessary to mention expressly that this festal rejoicing was also to be manifested in joyous sacrificial meals; it was enough for him to point to the blessing which God had bestowed upon their cultivation of the corn, the olive, and the vine, and upon all the works of their hands, i.e., upon their labour generally (Deuteronomy 16:13-15), as there was nothing further to remark after the instructions which had already been given with reference to this feast also (Leviticus 23:34-36, Leviticus 23:39-43; Numbers 29:12-38).
Geneva Study BibleThou shalt {g} observe the feast of tabernacles seven days, after that thou hast gathered in thy corn and thy wine: (g) That is, the 15th day of the seventh month, Le 23:34.
King James Translators' Notescorn...: Heb. floor, and thy winepress
Jamieson-Fausset-Brown Bible Commentary13-17. Thou shalt observe the feast of tabernacles seven days-(See on [147]Ex 23:14; [148]Le 23:34; [149]Nu 29:12). Various conjectures have been formed to account for the appointment of this feast at the conclusion of the whole harvest. Some imagine that it was designed to remind the Israelites of the time when they had no cornfields to reap but were daily supplied with manna; others think that it suited the convenience of the people better than any other period of the year for dwelling in booths; others that it was the time of Moses' second descent from the mount; while a fourth class are of opinion that this feast was fixed to the time of the year when the Word was made flesh and dwelt-literally, "tabernacled"-among us (Joh 1:14), Christ being actually born at that season.
Matthew Henry's Concise Commentary16:1-17 The laws for the three yearly feasts are here repeated; that of the Passover, that of the Pentecost, that of Tabernacles; and the general law concerning the people's attendance. Never should a believer forget his low estate of guilt and misery, his deliverance, and the price it cost the Redeemer; that gratitude and joy in the Lord may be mingled with sorrow for sin, and patience under the tribulations in his way to the kingdom of heaven. They must rejoice in their receivings from God, and in their returns of service and sacrifice to him; our duty must be our delight, as well as our enjoyment. If those who were under the law must rejoice before God, much more we that are under the grace of the gospel; which makes it our duty to rejoice evermore, to rejoice in the Lord always. When we rejoice in God ourselves, we should do what we can to assist others also to rejoice in him, by comforting the mourners, and supplying those who are in want. All who make God their joy, may rejoice in hope, for He is faithful that has promised. | 
