What "it" refers to

Hello....

What does the "it" refer to in the passage below?

I know it's very esoteric....

Not usual English text....

But, without any prior knowledge, just as a native speaker, I wonder what will be the answer.

Does “it” refer to “fear”?

Or maybe “fear of God”?

Or... maybe this passage is just bad English?

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To look upon the fear of GOD does need some preparation. Only the sane can look on stark insanity and raving madness with pity and compassion, but not with fear. For only if you share in it does it seem fearful, and you do share in it until you look upon each other with perfect faith and love and tenderness.