John Wesley on Deuteronomy 29:15

So also - With your posterity. For so the covenant was made at first with Abraham and his seed, by which as God engaged himself to continue the blessing of Abraham upon his posterity, so he also engaged them to the same duties which were required of Abraham. So it is even among men, where a king confers an estate upon a subject and his heirs for ever, upon some certain conditions, all his heirs who enjoy that benefit, are obliged to the same conditions. It may likewise include those who were then constrained to be absent, by sickness, or any necessary occasion. Nay one of the Chaldee pharaphrasts reads it, all the generations that have been from the first days of the world, and all that shall arise to the end of the whole world, stand with us here this day. And so taking this covenant as a typical dispensation of the covenant of grace, 'tis a noble testimony to the Mediator of that covenant, who is the same yesterday, to day, and for ever.