Charles Ellicott Commentary 2 Samuel 10:8

"And the children of Ammon came out, and put the battle in array at the entrance of the gate: and the Syrians of Zobah and of Rehob, and the men of Tob and Maacah, were by themselves in the field." — 2 Samuel 10:8 (ASV)

At the entering in of the gate. —The Ammonites and their allies formed separate armies, the former taking their stand immediately before the city, the latter “by themselves” at some distance, where the ground was more favourable for the manoeuvres of their chariots.