They are all adulterers, like an oven heated by a baker who needs not stoke the fire from the kneading to the rising of the dough.
The Prophet pursues the same subject in this verse: he says that they were all adulterers. This similitude has already been often explained. He speaks not here of common fornication, but calls them adulterers, because they had violated their faith pledged to God, because they gave themselves up to filthy superstitions, and also, because they had wholly corrupted themselves, for faith and sincerity of heart constitute spiritual chastity before God.
Some take away the last words of the foregoing chapter, and make them the beginning of this: "When I returned, or would have returned, the captivity of my people, when I was about to come towards them in ways of mercy, even when I would have healed Israel, then the iniquity of Ephraim (the country and common people) was discovered, and the wickedness of Samaria...
Commenting on Hosea 7:1-7
They are all adulterers,.... King, princes, priests, and people, both in a spiritual and corporeal sense; they were all idolaters, given to idols try, eager of it, and constant in it, as the following metaphors show; and they were addicted to corporeal adultery; this was a prevailing vice among all ranks and degrees of men.