but this is what I commanded them: Obey Me, and I will be your God, and you will be My people. You must walk in all the ways I have commanded you, so that it may go well with you.
I spoke not then to your fathers, nor commanded them in the day I brought them forth from the land of Egypt, etc. The Prophet calls the attention of the Jews to the first condition of the Church; for though God had made his covenant with Abraham, Isaac, and Jacob, yet he then only formed or framed for himself a Church when the Law was promulgated.
God, having shown the people that the temple would not protect them while they polluted it with their wickedness, here shows them that their sacrifices would not atone for them, nor be accepted, while they went on in disobedience. See with what contempt he here speaks of their ceremonial service (Jer 7:21).
Commenting on Jeremiah 7:21-28
But this thing commanded I them, saying,.... This was the sum and substance of what was then commanded, even obedience to the moral law; this was the main and principal thing enjoined, and to which the promise was annexed: obey my voice: the word of the Lord, his commands, the precepts of the decalogue; obedience to which was preferable to the sacrifices of the ceremonial...