John Gill Commentary Deuteronomy 29:22

"And the generation to come, your children that shall rise up after you, and the foreigner that shall come from a far land, shall say, when they see the plagues of that land, and the sicknesses wherewith Jehovah hath made it sick;" — Deuteronomy 29:22 (ASV)

So that the generation to come of your children that shall
rise up after you
Not the next generation, but in future times, in ages to come, at a great distance, even after the destruction of Judea by the Romans; to which (Deuteronomy 29:23) seems to refer:

and the stranger that shall come from a far land ;
on trade and business, or for the sake of travelling, his road either lying through it, or his curiosity leading him to see it:

shall say, when they see the plagues of the land ;
cities and towns in ruins, fields lie uncultivated, and the whole land depopulated, and all become a barren wilderness, which was once a fruitful country, a land flowing with milk and honey:

and the sicknesses which the Lord has laid upon it ;
upon the inhabitants of it, as the pestilence and other diseases, which shall have swept the land of them; see (Deuteronomy 28:22Deuteronomy 28:27Deuteronomy 28:35) . This case supposes a general departure from the worship of God to the service of idols; otherwise single individuals are punished in their own persons, as in the (Deuteronomy 29:21) .