There is a lower world where fears are real -- where all things, and everyone living in this world, are unknowing participants in the fear that's found there. In this darker realm, the thing feared is inseparable from the nature that fears it, so that any action taken by this nature to end the fear it feels becomes the seed of its next fearful state.
For example, say that you're worried that someone you love may be losing interest in your affection. As this fear mounts, you start asking for emotional affirmation -- seeking through words or by touch the attention you fear is waning. This push for consolation, created entirely by fear, produces exactly the opposite reaction in your partner, and he or she withdraws further. Most of us already know how this story plays out: in the end, we unwittingly cause the very thing we most feared would happen.
There is a higher world where fears such as these can't enter, let alone infect. Its peace is inseparable from its wholeness because in the higher worlds holiness is perfect protection; no creature can come into it that hasn't agreed to be one with its harmony. Any action taken by this nature is always in accord with the innumerable worlds in and around it; as such, these actions are the seeds of that peaceable kingdom from which they are sown. In the truest sense of the words, this world is the peace that passes all understanding.
It isn't so much that we live between these two worlds as it is that we're unaware of living in these two worlds at the same time. The world below knows nothing of the world above, while the world above understands everything about what dwells beneath it.
Knowledge alone of these inner domains does nothing to change your relationship with them, other than help make intellectually clear which of these two kingdoms should be the object of your soul's affection. About this there should be no confusion, any more than one would struggle to decide whether to collect sharp pebbles or precious pearls from the shoreline. However, just as it's true that discerning the difference between a smooth pebble and a precious pearl requires being able to see them, so is it true when it comes to knowing the difference between what is fearful or fearless within you.
This is why only the light of awareness of the entangled existence of these worlds can lead you safely through them and into the holiness that you seek. This awareness is choice, and this choice is action; together, they are one movement that serves a single divine purpose: to deliver you from out of the fearful hands of the lower worlds and into the loving hands of heaven.