Jamieson, Fausset and Brown on Numbers 29:12-34

12-34. on the fifteenth day--was to be held the feast of booths or tabernacles. (See Le 23:34, 35). The feast was to last seven days, the first and last of which were to be kept as Sabbaths, and a particular offering was prescribed for each day, the details of which are given with a minuteness suited to the infant state of the church. Two things are deserving of notice: First, that this feast was distinguished by a greater amount and variety of sacrifices than any other--partly because, occurring at the end of the year, it might be intended to supply any past deficiencies--partly because, being immediately after the ingathering of the fruits, it ought to be a liberal acknowledgment--and partly, perhaps, because God consulted the weakness of mankind, who naturally grow weary both of the charge and labor of such services when they are long-continued, and made them every day less toilsome and expensive [Patrick]. Secondly, it will be remarked that the sacrifices varied in a progressive ratio of decrease every day.