Deuteronomy 16:13-15. THE FEAST OF TABERNACLES.
(13) Thou shalt observe the feast of tabernacles seven days. — For details of the observance see the passages already referred to in Exodus, Leviticus and Numbers, but more especially Leviticus 23:33-43.
(14) Thou, and thy son... — The rejoicing of the Feast of Tabernacles was proverbial among the Jews. On the persons who are to share the joy, Rashi has an interesting note. “The Levite, the stranger, and the fatherless, and the widow, — My four (Jehovah’s), over against thy four — thy son, thy daughter, thy manservant, thy maidservant. If thou wilt make My four to rejoice, I will rejoice thy four.”
(15) Seven days. — An eighth day is mentioned both in Leviticus 23:36 and Numbers 29:35. But the seven days of this feast are also spoken of in both those passages (Leviticus 23:36 and Numbers 29:12). There is, therefore, no contradiction between the two passages. The eighth day is treated apart from the first seven days of the Feast of Tabernacles, somewhat in the same way as the Passover is always distinguished in the Pentateuch from the six days which followed it, and which are called the Feast of Unleavened bread. The reason for the distinction in that case becomes clear in the fulfilment of the feast by our Lord. The Passover is His sacrifice and death. We keep the feast of unleavened bread by serving Him in “sincerity and truth.” The Feast of Tabernacles has not yet been fulfilled by our Lord like the two other great feasts of the Jewish calendar. Unfulfilled prophecies regarding it may be pointed out, as in Zechariah 14. Our Lord refused to signalise that feast by any public manifestation (John 7:2-10). There may, therefore, be some reason for separating the eighth and last day of the Feast of Tabernacles from the former seven, which will appear in its fulfilment in the kingdom of God. It is remarkable that the dedication of Solomon’s temple, the commencement of the second temple and the dedication of the wall of Jerusalem, all occurred about the time of the Feast of Tabernacles.
Thou shalt surely rejoice. — In the Hebrew this is a somewhat unusual form of expression. Literally, thou wilt be only rejoicing. Rashi says it is not a command, but a promise.