Jamieson, Fausset and Brown on Hosea 4:6

6. lack of knowledge--"of God" (Ho 4:1), that is, lack of piety. Their ignorance was wilful, as the epithet, "My people," implies; they ought to have known, having the opportunity, as the people of God.

thou--O priest, so-called. Not regularly constituted, but still bearing the name, while confounding the worship of Jehovah and of the calves in Beth-el (1Ki 12:29, 31).

I will ... forget thy children--Not only those who then were alive should be deprived of the priesthood, but their children who, in the ordinary course would have succeeded them, should be set aside.