Albert Barnes Commentary Jeremiah 41:1

"Now it came to pass in the seventh month, that Ishmael the son of Nethaniah, the son of Elishama, of the seed royal and [one of] the chief officers of the king, and ten men with him, came unto Gedaliah the son of Ahikam to Mizpah; and there they did eat bread together in Mizpah." — Jeremiah 41:1 (ASV)

The seventh month – Gedaliah’s government lasted less than two months.

Even – Rather, and. Ishmael was probably descended from Elishama, the son of David (2 Samuel 5:16). Ten grandees, each with his retinue, would have aroused suspicion, but the smallness of Ishmael’s following put Gedaliah completely off his guard.