Albert Barnes Commentary 2 Kings 15:25

"And Pekah the son of Remaliah, his captain, conspired against him, and smote him in Samaria, in the castle of the king`s house, with Argob and Arieh; and with him were fifty men of the Gileadites: and he slew him, and reigned in his stead." — 2 Kings 15:25 (ASV)

A captain of his - A mere “captain,” a person, therefore, of very moderate rank. The low birth of Pekah is probably alluded to in Isaiah’s favorite designation of him as “Remaliah’s son” (Isaiah 7:4–5, 9; 8:6).

From the fact that Pekah employed Gileadites to carry out his designs, it has been conjectured that he himself belonged to the trans-Jordanic region.

In the palace of the king’s house - Rather, “in the tower of the king’s palace,” or possibly “in the harem of the king’s palace” (see the note on 1 Kings 16:18).