When Jacob went to receive the blessings from Isaac, why did he not tell Isaac that he deserves the blessings because he had bought the seniority? According to what RASHI interprets on Esau’s saying, “This one delayed me twice,” meaning he took his seniority by deceit, and Isaac replied to him, “He, too, shall be blessed,” meaning that Isaac took the selling of the seniority into account, meaning that because of it, Jacob deserved the blessings.

Thus, why did Jacob not (say) to Isaac that he deserves the blessings because now he is the senior?

To understand the above, we should first interpret what is written in the name of the ARI, that Esau’s head is holy but his body is impure. Baal HaSulam explained that it is because each degree spreads to Rosh and Guf [head and body, respectively], where Rosh means when he is not receiving, and Guf means when the abundance is clothed in the Kelim [vessels].

The discernment of Rosh in the left line is always holy because Rosh means resistance to clothing. Only when it is received is it forbidden to accept the left line. This means that from the Peh and above, it is permitted to extend, but not from the Peh down.

This is why it is written, “And Isaac loved Esau for there was game in his mouth,” meaning he showed Isaac that he was receiving all the good things only up to the Peh, but not below the Peh.