Deuteronomy 29:15
But with him that standeth here with us this day before the LORD our God, and also with him that is not here with us this day: But with him that standeth here with us this day before the LORD our God, and also with him that is not here with us this day:
The covenant renewed before the Lord on that day was not confined to the Israelites who stood there in person, but reached also to those who were absent. It was Moses who renewed that covenant before God, and its scope deliberately embraced both the gathered assembly and those not gathered with them. The inclusion of the absent shows the covenant extended beyond the people physically present before God.
That covenant bound the people to the Lord and made them answerable for turning aside to other gods.