Jamieson, Fausset and Brown on Ezekiel 20:21

21. Though warned by the judgment on their fathers, the next generation also rebelled against God. The "kindness of Israel's youth and love of her espousals in the wilderness" (Jr 2:2, 3) were only comparative (the corruption in later times being more general), and confined to the minority; as a whole, Israel at no time fully served God. The "children" it was that fell into the fearful apostasy on the plains of Moab at the close of the wilderness sojourn (Nu 25:1, 2; De 31:27).