Rabbi Shimshon David Pincus, zt"l
"Your G-d and the G-d of your father gave you a hidden treasure in your sacks. Your money came to me." (43:23)
Why did Yosef return their money, putting it in the mouths of their grain sacks? Ostensibly it was just to cause them consternation, and was part of the process Yosef was putting them through until he revealed his true identity. Because here they are, trying to return the money to him, and, as we see from the continuation of the story, he could very well have accepted it, and given it back to them at a later point.
Why did he insist on refusing the money, offering a strange and untruthful excuse? He told them, “Your G-d and the G-d of your father gave you a hidden treasure in your sacks. Your money came in to me.” This is such a bizarre claim. The money in your hands must have fallen from Heaven; I already received your payment.
Yosef really went out of his way not to take money back from them so he must have had a good reason for this.
Chazal call Yosef by the name of Yosef Hatzaddik. Tzidkus is his special trait. Chazal say about the tzaddik: The whole world stands on one pillar, and it is called “tzaddik,” as it says: וצדיק יסוד עולם – “The tzaddik is the foundation of the world.”
It says also about Noach that he was a tzaddik: נח איש צדיק – “Noach was a righteous man.” He supported and fed the whole world on his own during the Mabul. It seems that Yosef had a similar desire. He wanted to uphold his special midah and support the whole world. Noach, who was a small tzaddik, supported a small world, within the teivah. Yosef, who was a great tzaddik, supported and fed the whole wide world.
However, as long as Yosef sold food to people for money, it was not really the act of a tzaddik. Only when the whole world ran out of money, as Chazal say, and he still supported and fed them, then it was truly the act of a tzaddik.
Yet, the trait of tzaddik was still incomplete, because his brothers came to him with money to buy grain. This is why it was important to Yosef to return their money to them. He wished to fulfill his role and trait of צדיק יסוד עולם
