I hewed them by the prophets - that is, I announced by the prophets that they should be hewn asunder, like trees of the forest. God identifies His act with that of His prophets; the word being His instrument for executing His will (Jer 1:10; Eze 43:3).
by ... words of my mouth - (Isa 11:4; Jer 23:29; Heb 4:12).
thy judgments - the judgments which I will inflict on thee, Ephraim and Judah (Hos 6:4). So “thy judgments,” that is, those inflicted on thee (Zep 3:15).
are as the light, etc. - like the light, palpable to the eyes of all, as coming from God, the punisher of sin. Henderson translates, “lightning” (compare Margin, Job 37:3, Job 37:15).