Pesachim 65 - 71
“A person who is haughty — if he is wise, his wisdom will depart from him; and if he is a prophet then his power of prophecy will depart from him.”
This statement taught by Rav Yehuda in the name of Rav is brought on our daf as an example of what transpired with Hillel when he was appointed leader of the Sanhedrin and spoke with a degree of haughtiness to the previous leaders, the sons of Ben Betera. He was subsequently punished by Heaven by forgetting what he had learned from his teachers Shamaya and Avtalyon regarding transporting the knife for the Korban Pesach when the eve of Pesach occurred on Shabbat.
- Pesachim 66b
“Rabbi Shimon ben Lakish said: Any person who becomes angry — if he is wise, his wisdom will depart from him; if he is a prophet then his power of prophecy will depart from him.”
Our gemara explains that the Sage learns the first part of his teaching from Moshe Rabbeinu. When the Jewish army came back victorious from their battle with Midian, Moshe expressed anger with them for not precisely carrying out his orders. As a result, he was punished from Above and the laws of “tevillat keilim” — ritual immersion of the vessels taken as spoils of the war — were forgotten by him and were taught to the Jewish People by Elazar the Kohen instead of by Moshe.
- Pesachim 66b