If the purpose of the creation of the worlds is to delight His creatures, then why did He create this corporeal, turbid, and tormented world? Without it, He could certainly delight the souls as much as He wanted; why did He bring the soul into such a foul and filthy body?
The sages explained it with the verse, “One who eats that which is not one’s own, is afraid to look upon one’s face.” It means there is a flaw of shame in any free gift. In order to spare the souls this blemish, He has created this world, where there is work. They will therefore enjoy their labor for they take their pay from the Whole, in return for their work, and are thus spared the blemish of shame.
– Baal HaSulam, The Study of the Ten Sefirot, Part 1, “Inner Reflection,” Chapter 1, Item 6