Charles Ellicott Commentary 2 Kings 9:6

"And he arose, and went into the house; and he poured the oil on his head, and said unto him, Thus saith Jehovah, the God of Israel, I have anointed thee king over the people of Jehovah, even over Israel." — 2 Kings 9:6 (ASV)

And he arose — that is, Jehu arose.

Into the house. — The council of war was sitting in the court.

I have anointed thee. — The commission to Elijah (1 Kings 19:16) was thus fulfilled by his successor.

Over the people of the Lord. — Israel being Jehovah's people, Jehovah was Israel’s true king, and therefore it was within His sovereign right to appoint whomever He willed as His earthly representative. Reuss asserts that this account of the anointing of Jehu, like that of the anointing of Hazael (2 Kings 8:13), is substituted in the present narration for what another document related of Elijah. This is pure conjecture.

It is easier to suppose that Elijah had instructed his successor to carry out the commission entrusted to himself, although the narrative nowhere says so. He goes on to remark that there is no need to try to clear Elisha of the charge of being a revolutionary and a regicide, because the new dynasty would make use of his name by way of legitimizing itself, exactly as the houses of Kish and of Jesse made use of that of the prophet Samuel. This is to be considerably wiser than our only authorities.