﴿ وَتَكُونُ ٱلْجِبَالُ كَٱلْعِهْنِ ٱلْمَنفُوشِ ﴾

“and the mountains will be like fluffy tufts of wool....”

and the mountains will be like tufts of wool like carded wool in terms of the lightness with which it floats in the air until it comes to settle upon the earth.