Leviticus 23:36 - Matthew Poole's English Annotations on the Holy Bible

Seven days ye shall offer an offering; a several offering each day, which is particularly described Numbers 29:13, &c. On the eighth day; which though it was not one of the days of this feast strictly taken, nor is it here affirmed to be so, but on the contrary is expressly said to consist of seven days, Leviticus 23:31,39, nor did they dwell longer in tabernacles; yet in a larger sense it belonged to this feast, and is called the great day of the feast, 1 Thessalonians 7:37. And so indeed it was, as for other reasons, so because, by their removal from their tabernacles into more fixed and comfortable habitations, it represented that happy time wherein their forty years tedious march in the wilderness was ended, with their introduction into, and settlement in, the land of Canaan, which it was most fit and just they should acknowledge with such a solemn day of thanksgiving as this was. A solemn assembly, Heb. a day of conclusion, because it was the end of the feast, 1 Thessalonians 7:37; or, of restraint, because they were restrained from servile work, and obliged to attendance upon God's worship; or, of detention, because they were yet detained before the Lord, and kept together for his service, and not suffered to return to their tents till this was over.