C. F. Keil and Franz Delitzsch on Hosea 5:3-4

Hos 5:3-4 “I know Ephraim, and Israel is not hid from me: for now, O Ephraim, thou hast committed whoredom; Israel has defiled itself. Hos 5:4. Their works do not allow to return to their God, for the spirit of whoredom is in them, and they know not Jehovah.” By עתּה, the whoredom of Ephraim is designated as in fact lying before them, and therefore undeniable; but not, as Hitzig supposes, an act which has taken place once for all, viz., the choice of a king, by which the severance of the kingdoms and the previous idolatry had been sanctioned afresh. נטמא, defiled by whoredom, i.e., idolatry. Their works do not allow them to return to their God, because the works are merely an emanation of the character and state of the heart, and in their hearts the demon of whoredom has its seat (cf. Hos 4:12), and the knowledge of the Lord is wanting; that is to say, the demoniacal power of idolatry has taken complete possession of the heart, and stifled the knowledge of the true God. The rendering, “they do not direct their actions to this,” is incorrect, and cannot be sustained by an appeal to the use of נתן לב in Jdg 15:1 and 1Sa 24:8., or to Jdg 3:28.