Chapter 31;v.31

וַיֹּאמֶר אֶלְעָזָר הַכֹּהֵן אֶל־אַנְשֵׁי הַצָּבָא הַבָּאִים לַמִּלְחָמָה זֹאת חֻקַּת הַתּוֹרָה אֲשֶׁר־צִוָּה יְהֹוָה אֶת־מֹשֶֽׁה

And Eleazar the priest said to the men of war which went to the battle, This is the ordinance of the Torah which the Lord commanded Moses

Reish Lakish said: “Anyone who gets angry – if he is a wise man, his wisdom departs from him, as it is written (verse 14) “Moses was very angry”, then “And Elazar the priest said: this is the law of the Torah that God commanded Moses”. It seems from this that [Elazar said this law which] Moses had forgotten (Talmud Pesachim 66b).

אמר ריש לקיש: כל אדם שכועס – אם חכם הוא, חכמתו מסתלקת ממנו, דכתיב (פ’ י”ד): “ויקצף משה”, וכתיב: “ויאמר אלעזר הכהן: זאת חקת התורה אשר צוה ה’ את משה” – מכלל דמשה נעלמת ממנו הלכה.