שמואל ב כ:טו פירוש: רש״י

And it [the city] held by virtue of its inner wall. [Yonoson translates:] "They surrounded it strongly." Some interpret וַתַּעֲמדׁ בַּחֵל to have a meaning like "the inner wall and the outer wall".⁷Eichoh 2:8. They had [already] cause the outer wall to fall and it [the city] fortified itself to hold fast by virtue of the inner wall.