When Ephraim spake trembling, he exalted himself in Israel; but when he offended in Baal, he died.
This chapter and Hosea 14:1-9 probably belong to the troubled times that followed Pekah's murder by Hoshea (cf. Hosea 13:11; 2 Kings 15:30). The subject is the idolatry of Ephraim, notwithstanding God's past benefits, destined to be his ruin. When Ephraim spake trembling - rather, 'When Ephraim (the tribe most powerful among the twelve in Israel's early history) spake (authoritatively) there was trembling (cf. Joshua 4:14; Daniel 5:19); all reverentially feared him' (Jerome). (Compare Job 29:8-9; Job 29:21.) Ephraim, all along in history, was characterized by pride (Hosea 5:5, "The pride of Israel doth testify to his face: therefore shall Israel and Ephraim fall in their iniquity"). At no time could it be well said, "Ephraim spake trembling."
But when he offended in Baal - i:e., in respect to Baal, by worshipping him (1 Kings 16:31) under Ahab: a more heinous offence than even the calves. Ahab having married Jezebel, the daughter of Ethbaal, the king of the Zidonians, "as if it had been a light thing for him to walk in the sins of Jeroboam the son of Nebat, he went and served Baal (the Zidonian idol), and worshipped him." Therefore, it is at this climax of guilt that Ephraim "died." Sin has, in the sight of God, within itself the gem of death, though that death may not visibly take effect until long after. Compare Romans 7:9, "Sin revived, and I died." So Adam in the day of his sin was to die, though the sentence was not visibly executed until long after (Genesis 2:17, "In the day that thou eatest thereof (of the tree of knowledge of good and evil), thou shalt surely die;" Genesis 5:5, "All the days that Adam lived were nine hundred and thirty years, and he died"). Israel is similarly represented as politically dead, in Ezekiel 37:1-28.