Then they hasted, and took every man his garment, and put it under him on the top of the stairs, and blew with trumpets, saying, Jehu is king.

Wesley's Notes

9:13 They hasted - God putting it into their hearts thus readily to own him. Under him - Under Jehu. A ceremony used in the eastern parts towards superiors, in token of reverence to his person, that they would not have his feet to touch the ground, and that they put themselves and their concerns under his feet, and into his disposal. The stairs - In some high and eminent place, whence he might be seen and owned by all the soldiers, who were called together upon this great occasion.

King James Translators' Notes

is king: Heb. reigneth

Jamieson-Fausset-Brown Bible Commentary

13. they hasted, and took every man his garment-the upper cloak which they spread on the ground, as a token of their homage to their distinguished commander (Mt 21:7).

top of the stairs-from the room where the prophet had privately anointed Jehu. That general returned to join his brother officers in the public apartment, who, immediately on learning his destined elevation, conducted him to the top of the stairs leading to the roof. This was the most conspicuous place of an Oriental structure that could be chosen, being at the very top of the gate building, and fully in view of the people and military in the open ground in front of the building [Kitto]. The popularity of Jehu with the army thus favored the designs of Providence in procuring his immediate and enthusiastic proclamation as king, and the top of the stairs was taken as a most convenient substitute for a throne.

Matthew Henry's Concise Commentary

9:11-15 Those who faithfully deliver the Lord's message to sinners, have in all ages been treated as madmen. Their judgment, speech, and conduct are contrary to those of other men; they endure much in pursuit of objects, and are influenced by motives, into which the others cannot enter. But above all, the charge is brought by the worldly and ungodly of all sorts, who are mad indeed; while the principles and practice of the devoted servants of God, prove to be wise and reasonable. Some faith in the word of God, seems to have animated Jehu to this undertaking.