What does Jesus mean by the awful horror?

We were on a dry and barren rocky edge. The ground broke off abruptly. All light ceased, and tiny particles of mist appeared to pile themselves up into a great wall against the darkness. There was no intermingling of light and dark, simply this awful darkness, which seemed as if it were a solid curtain―or even a wall against which the light piled itself up, but could not penetrate. Go to the uttermost edge of that rocky cliff and stretch out your hand into the darkness. 

I went to the edge and felt the hand of my guide resting on my shoulder to steady me. 

My hand went into the darkness and was immediately lost to sight. Where my arm entered the darkness, I felt a narrow band of intense numbing, and yet burning cold.

Why this darkness and cold? The light of faith does not exist here―there is no love of God.

The wall of darkness began to sway to and fro slowly. There was no interpenetration, simply an undulating line. As this movement grew more and more violent, I sprang back from the cliff, fearing that a fold of darkness might engulf me. 

Stand firm. The darkness cannot reach us―there is too much faith here. As you are now a spirit, you need the spiritual light and warmth, just as on earth you needed physical warmth and light.

And so it was, for though the folds of darkness swept up on either side of the spot where we were standing, it never engulfed us, and we were able to realise the awful depth of the precipice. 

A ball of light began to emerge out of the darkness beneath us. 

Mounting rapidly, we saw it was a glorious spirit of light. As he rose from the depths, the darkness seemed to fall off him like water from a duck’s back. Having climbed over the edge of the cliff to its top, he lay down and stretched his arm down into the darkness. It vanished up to the shoulder. As he withdrew his arm, we saw that his hand grasped another’s. The newcomer’s hand was dark and dirty with a pallid and unhealthy tinge. Slowly and painfully, a miserable object struggled up beside him. His eyes were covered with a bandage. He fell to the ground beside his guide who rose to his feet and gently helped him up. The newcomer wore a dark grey ragged garment, which was covered with stains and seemed to have patches of darkness still clinging to it.

You cannot realise how intense all these experiences are. I cannot convey to you the awful horror of that darkness.

It was a horror, which seemed to choke and freeze me. It was awful beyond measure.