Charles Ellicott Commentary Deuteronomy 5:3

"Jehovah made not this covenant with our fathers, but with us, even us, who are all of us here alive this day." — Deuteronomy 5:3 (ASV)

Not ... with our fathers, but with us. —That is, according to the usage of the Hebrew language in drawing contrasts, not only with our fathers (who actually heard it), but with us also, who were, by descent, in our fathers, and for whom the covenant was intended no less than for them; and, in fact, every man who was above forty-two at the time of this discourse might actually remember the day at Sinai.