Let us imagine that scene, when a denier sees the fire burning and throwing sparks even that some of its parts are burning the others. While this denier stands in a shade which he mistakenly thinks that it will protect him from the flames. The fire will throw sparks and lava against those waiting to be thrown in it. Thes sparks are not normal, they are described as fortress because of their greatness.

(  a fortress … ) (…a fortress): The spark is as a palace in its greatness and big size. Another meaning of this Arabic word is the trucks of the trees that exist in the desert. When winter comes, the branches of these trees are cut and their trunks remain which look like the camel when it sits in the desert.