In a purely historical narrative such as that in Exodus, a condensed statement of what took place on this occasion was sufficient; but in an address to the people, it was fitting that Hoses should give it in fuller detail, especially in view of what follows.
The words of God in reply to those of the people are not given in Exodus; here they are fittingly inserted God approved of their words because they expressed a proper reverence and m due sense on their part of the unworthiness of sinful men to come into the presence of the great and holy God; but knowing their fickleness, and proneness to forget and depart from him, he added, Oh that there were such an heart in them that they would fear me and keep all my commandments always! God looks upon the heart, and will accept no service or worship that is not rendered from the heart. Only they who do his will from the heart (Ephesians 6:6) really fear and keep his commandments. The tongue may sometimes promise what the heart does not guarantee; and so when the occasion that provoked the utterance has passed, the whole may be forgotten, and the promise never be fulfilled.
The people were commanded to return to their tents, and Moses was appointed to act as mediator between God and them, receiving from him his commandments and communicating them to the people.
Moses winds up this part of his discourse by exhorting them to observe and do all God's commandments, not in any way departing from that course of action to which he had called them, that they might live, and it should be well with them in the land they were about to possess.