John Gill Commentary 2 Kings 9:31

"And as Jehu entered in at the gate, she said, Is it peace, thou Zimri, thy master`s murderer?" — 2 Kings 9:31 (ASV)

And as Jehu entered in at the gate
Either of the city of Jezreel, or of the king's palace:

she said, [had] Zimri peace, who slew his master ?
Elah the son of Baasha king of Israel; no, he had not; he reigned but seven days, and, being besieged, burnt the king's house over him, and died, (1 Kings 16:10 1 Kings 16:18) , suggesting that the like would be his fate, who had slain his master Joram; or the words may be rendered, "O Zimri, the slayer of his master"; calling Jehu so, because of his likeness to Zimri.