Albert Barnes Commentary Hosea 10:4

"They speak [vain] words, swearing falsely in making covenants: therefore judgment springeth up as hemlock in the furrows of the field." — Hosea 10:4 (ASV)

They have spoken words - The words which they spoke were eminently words; they were mere words, which had no substance; swearing falsely in making a covenant (literally, “swearing falsely, making a covenant”), and judgments spring up as hemlock in the furrows of the field.

Consequently: “There is no truth in words, no sanctity in oaths, no faithfulness in keeping covenants, no justice in giving judgments.” Such is the result of all their oaths and covenants, that judgment springs up, yes, flourishes. But what judgment? Judgment, bitter and poisonous as hemlock, flourishes, as hemlock would flourish on ground broken up and prepared for it.

They break up the ground, make the furrows. They will not have any chance self-sown seed; they prepare the soil for harvest, full, abundant, regular, cleared of all besides. And what harvest? Not any wholesome plant, but poison. They cultivate injustice and wickedness, as if these were to be the fruits to be rendered to God from His own land. So Amos says, You have turned judgment into gall or wormwood (Amos 6:12); (Amos 5:7). And Habakkuk says, Judgment went forth perverted (Habakkuk 1:4).