Truth.

No one knows where we can from, why we're here, or what the future holds.  Yet people identify with their own opinions of conceptual things in this world we live in as closely as they are attached to their own skin.  If those same people knew the real truth, or even more important that there is no reality, that this is all just an illusion (what we perceive as reality), then they would experience true freedom.  To not identify with a thing is to separate yourself from that thing.  To know that you are not this body, this form, is to realize that you are just the conscious spirit (and one with the source of all life) that is using this body for a little while, is to see that there is more to knowing than anything conceptual your mind can come up with.  To be trapped in the mind, like most people are, is to be a slave to it.  Free yourself from it...and you will have the peace that surpasses all understanding.