If we look straight out, our eyes can see forever. Infinity is a very long distance. At a certain point, our mind will put up a barrier, just because dealing with infinity is beyond our cognitive abilities. Once this barrier is in place, reality is divided into discrete identities. We develop emotional attachments to these entities, and wish to preserve them. This is the quality of mercy. The tension between things being preserved and their dissolution back into the infinite creates the temporary world of form.
Fear is both our memory of the undivided swirling majesty of the infinite, as well as our knowledge that our division of that infinite creates things that are "us" and "not us". Fear manifests as both a knowledge of objects, and a knowledge of the unknowable. For me, the most frightful memory I have is of a phone call: both the fact that there is something very definite to which I must respond, and the fact that this very definite refers to something which I do not know.
Fear is what keeps our boundaries. If we do not listen to that fear, that knowledge that there is something imminent that is not us, we will face the second type of fear, the fear that destroys all boundaries. | 
