My people are destroyed for lack of knowledge: because thou hast rejected knowledge, I will also reject thee, that thou shalt be no priest to me: seeing thou hast forgotten the law of thy God, I will also forget thy children.
My people are destroyed for lack of knowledge - literally, 'THE knowledge,' the only true and saving knowledge, the knowledge "of God" (Hosea 4:1), i:e., lack of piety. The verb is plural both in the Hebrew and the English versions, 'are,' not 'is.' The plural implies that the individuals, as well as the collective whole "people," were one and all void of knowledge of God. Compare Isaiah 5:3; John 17:3. Their ignorance was willful, as the epithet, "my people," implies: they ought to have known, having the opportunity, as being the people of God, and taught by the prophet of God ("thy people," Hosea 4:4).
Because thou hast rejected knowledge, I will also reject thee, that thou shalt be no priest to me - `I will utterly reject thee' х wª'em'aacª'kaa (H3988)] (Pusey). God repays them in kind. As they rejected Him, so He will reject them.
Thou - O priest, so called. Not regularly constituted, but still bearing the name, while confounding the worship of Yahweh and of the calves in Beth-el (1 Kings 21:29,31).
Seeing thou hast forgotten the law of thy God, I will also 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-literally, 'I will forget thy children, I too.' God is said to "forget" when He treats men as if He no more bore them in mind, or exercised His loving-kindness toward them.