As I see it, the official function of this simile is to give us a sense of the size of Satan's shield and thereby to give us a sense of the size of Satan himself.

在我看来，这个比喻的正式的作用,是要给我们展现出撒旦的屏障的规模,因此来展现撒旦自身的伟岸。

耶鲁公开课 - 弥尔顿课程节选