Jehu's zeal
Whether Jehu's slaughter is commended as zeal or punished, as Hosea announces.
Hosea 1:4-5
4Yahweh said to him, “Call his name Jezreel; for yet a little while, and I will avenge the blood of Jezreel on the house of Jehu, and will cause the kingdom of the house of Israel to cease.
5It will happen in that day that I will break the bow of Israel in the valley of Jezreel.”
2 Kings 10:28-31
28Thus Jehu destroyed Baal out of Israel.
29However, Jehu didn’t depart from the sins of Jeroboam the son of Nebat, with which he made Israel to sin, the golden calves that were in Bethel and that were in Dan.
30Yahweh said to Jehu, “Because you have done well in executing that which is right in my eyes, and have done to Ahab’s house according to all that was in my heart, your descendants shall sit on the throne of Israel to the fourth generation.”
31But Jehu took no heed to walk in the law of Yahweh, the God of Israel, with all his heart. He didn’t depart from the sins of Jeroboam, with which he made Israel to sin.
What each tradition says
Rabbinic / Midrashic
Rashi reads “blood of Jezreel” as the blood of Ahab’s house, whom Jehu killed in Jezreel because they worshipped Baal. Since Jehu and his sons later worshipped pagan deities, God counts that blood as innocent blood.
Rashi (Rabbi Shlomo Yitzchaki), The Judaica Press complete Tanach with Rashi, translated by A. J. Rosenberg — Sefaria (Rashi on Hosea) — On Hosea 1:4
Patristic
No sourced position found. Checked CCEL NPNF 1/6 (Augustine: Sermon on the Mount, Harmony of the Gospels, Homilies), NPNF 1/10 (Chrysostom on Matthew) and NPNF 1/14 (Chrysostom on John) full texts for Jehu/Jezreel — no occurrence; a search for Chrysostom/Augustine/Jerome on Hosea 1:4 found only Jerome's etymology of "Jezreel" surviving as a second-hand citation in later commentaries, with no public-domain English text of his Hosea commentary.
Catholic
Haydock explains that Jezrahel is where Jehu slew Joram. Though Jehu was the instrument of God’s justice, he acted through malice and ambition. He was therefore deservedly punished.
George Leo Haydock, George Haydock's Catholic Bible Commentary (1859) — On Hosea 1:4
Orthodox
No sourced position found. Checked archive.org for public-domain English Eastern commentaries on the Twelve Prophets: Theodoret and Cyril of Alexandria exist only in modern 2000s translations, Theophylact and Euthymius in none; plus the CCEL NPNF full texts (Augustine, Chrysostom) — no orthodox statement on Hosea 1:4 / 2 Kings 10 found.
Reformed / Protestant
Calvin says Jehu became content with his prey and, having seized the kingdom, confirmed idolatry and every abomination. Because Jehu did not spend his labor for God, that slaughter was robbery with regard to Jehu, yet with regard to God it was a just revenge.
John Calvin, Commentary on Hosea (Calvin Translation Society; Christian Classics Ethereal Library) — On Hosea 1:4
Evangelical
Wesley says “the blood” means the slaughters Jehu did or ordered at Jezreel. Jehu’s house had possessed the throne through Jehoahaz, Jehoash, and Jeroboam; but the usurper and his successors held to Jeroboam son of Nebat’s idolatry and added other sins, provoking God to declare the family’s sudden extirpation.
John Wesley, John Wesley's Notes on the Bible (Wesley Center Online) — On Hosea 1:4