Albert Barnes Commentary Deuteronomy 12:8

"Ye shall not do after all the things that we do here this day, every man whatsoever is right in his own eyes;" — Deuteronomy 12:8 (ASV)

Moses points out that previously they had not observed the prescribed order in their worship, because during their migratory life in the wilderness it had been impossible to do so. During their wanderings there were undoubtedly times when the tabernacle was not set up for several days at a time, and when the daily sacrifice (Numbers 28:3), together with many other ordinances, were necessarily omitted .

This consideration must be carefully kept in mind throughout Deuteronomy. It illustrates the necessity for a repetition of very much of the Sinaitic legislation and suggests the reason why some parts are so urgently reiterated and stressed, while others are left unnoticed. Moses now warns the people that as they were about to leave their unsettled way of life, God’s purpose of choosing for Himself a place to set His Name there would be carried out, and the whole of the sacred ritual would consequently become binding. The rest and safety of Canaan is significantly set forth (Deuteronomy 12:10–11) as the essential condition and basis for a complete fulfillment of the Law: the perfection of righteousness thus coinciding with the end of wanderings, dangers, and hardships.