Two Opposites
There are two opposites in above reason—in mind and in heart, which is regarded as “for he desires mercy.” If foreign thoughts come to a person, he should remove them from him and not listen to them at all.
This is a hard work because Pharaoh king of Egypt afflicts them and throws foreign thoughts at them in mind and in heart, as it is written, “And the children of Israel sighed from the work, and their cry went up to God.” This is one side by which they are rewarded with faith, meaning the exodus from Egypt, and this is regarded as a soul of Kedusha [holiness].
On the other hand, “a soul without knowledge is not good, too,” and we need the knowledge of Kedusha, which is called “wealth,” for there is no wealth except in Daat [reason/knowledge]. When the Creator wanted to enrich them, they did not have Kelim [vessels] because everything was for them above reason, so the Creator gave them the advice to borrow Kelim from the Egyptians.
The taking of the Kelim was only so they would be able to receive a filling for the Kelim, meaning answers to their questions. But once they took the answers, they immediately returned the Kelim to the Egyptians. Because they are going above reason, they have no questions and they took the questions of the Egyptians only temporarily and then returned them.