“On the fifteenth day of the seventh month you shall have a holy convocation. You shall not do any ordinary work, and you shall keep a feast to the LORD seven days.
12. And on the fifteenth, day. Amongst their festivals this last was the chief “La plus authentique.” — Fr. in which they dwelt in tabernacles for seven days; for whereas in the Passover they commemorated the night in which they came forth free from the plagues of Egypt, by dwelling in tabernacles they embraced the whole forty years in which their fathers in the desert...
Soon after the day of atonement, that day in which men were to afflict their souls, followed the feast of tabernacles, in which they were to rejoice before the Lord; for those that sow in tears shall soon reap in joy.
Commenting on Numbers 29:12-40
On the eighth day ye shall have a solemn assembly,.... The day after the seven days of the feast of tabernacles were ended; for this was not properly a part of that feast, but was a sort of appendage to it: ye shall do no servile work therein; See Gill on Lev 23:36.