Or HaChaim on Deuteronomy 5:3/אור החיים על דברים ה׳:ג׳

1 לא את אבותינו כרת ה׳ את הברית הזאת, "G'd did not conclude this covenant with our fathers, etc." Rashi adds the word לבד. He means that G'd concluded the covenant "not only with our fathers." This is problematical as there was no need for the Torah to write this seeing it had already referred to the covenant G'd concluded "with us" in verse 1. According to my explanantion that the covenant mentioned in verse one refers to the covenant in Exodus 34,10 that G'd would not allow His presence to rest on the Gentile nations, we can understand the sequence of these verses as follows: "G'd did not specifically conclude this covenant with our fathers as we do not find this spelled out anywhere. As a result the reference in verse one to G'd having concluded a covenant with us was not sufficient as the word עמנו, "with us," does not preclude G'd from concluding similar covenants with other nations. Moses therefore went on record in our verse that the covenant he is talking about is indeed an exclsuive covenant between G'd and Israel. The principal message of the verse is that the present generation was given an assurance which even their fathers had not been given.

2כלנו חיים, "all of us who are alive." How could Moses say this? All the people with whom G'd had made the original covenant were dead already as they had died in the desert? Besides, many of the people who faced Moses at this time had not even been born at the time G'd concluded the original covenant with the Jewish people! While one could answer that what Moses said applied only to part of the people, this would be a forced explanation. Besides, what news did Moses convey to people by telling them they were all alive? Did they not know this without having to be told?

3Perhaps we may say that Moses emphasised that all of them who had heard the voice of G'd at the time of the revelation at Mount Sinai and who were alive at this time had survived that experience. This in spite of the fact that G'd had spoken to them out of fire, etc, i.e. that the experience had been extremely overpowering. The words כלנו חיים therefore must be understood as belonging to what follows in verse 4 rather than to what preceded it.