Albert Barnes Commentary 2 Kings 6:26

"And as the king of Israel was passing by upon the wall, there cried a woman unto him, saying, Help, my lord, O king." — 2 Kings 6:26 (ASV)

The walls of fortified towns had a broad space at the top, protected on the outside by battlements, along which the majority of the defenders were stationed, and from where they hurled their missiles and shot their arrows. The king seems to have been making his rounds to inspect the state of the garrison and the defenses.