Four sages entered paradise (פרדס, pronounced pardes, lit., orchard) in attempt to rectify Adam's primordial sin. Only one, Rabbi Akiva, entered in peace and came out in peace.
One died, one went insane, and one became a heretic. What protected Rabbi Akiva? What was his secret?
Before Rabbi Akiva set out on his spiritual journey, before commencing his ascent into the higher worlds, he committed himself never to transgress God's will, never to reach beyond the borders of his mind and soul, those borders that God had set for him.
Although his mental and spiritual worlds were continuously expanding due to his intense devoted effort to comprehend more and more of the mysteries of creation and the Creator, an ever expanding universe still remains limited.
The more accelerated the expansion of our inner universe, the harder it is for us to recognize our limitations at any given moment. But God knows when we have reached our border, and He signals us that it is time to stop and return, just that we have to be able to pick up His signal.
True commitment to God and self-nullification in His Presence endows us with an inner sense to feel when we have reached our border. At the critical moment we receive God's signal and know that we have gone as far as we can go and that now is the time to return, in peace.
Our commitment to return must precede our run upward. Whilst running up to God we need not have in mind the return that will follow (the thought of return in the midst of the run will weaken the forcefulness of the run). But the commitment is there all the time in our unconscious mind and it comes to the fore of our conscious mind exactly at the right moment. This is the secret of Rabbi Akiva.