Bava Batra 79A

עד נפח״⁠ – עד שתבא אש שאינה צריכה ניפוח, ״עד מידבא״⁠ – עד שתדאיב נשמתן. ואמרי לה: עד דעביד מאי דבעי.

even until Nophah,” meaning until the fire comes that does not require fanning [nippuaḥ], i.e., the fire of Gehenna, which will consume them. “Until Medeba [Medeva]”; this means until their souls are pained [tadiv]. And some say an alternative explanation: It means until God does what He wishes [mai deva’ei] with them and punishes them as they deserve.

אמר רב יהודה אמר רב: כל הפורש מדברי תורה ⁠– אש אוכלתו, שנאמר: ״ונתתי [את] פני בהם, מהאש יצאו והאש תאכלם״.

Rav Yehuda says that Rav says: With regard to anyone who separates himself from matters of Torah, a fire consumes him, as it is stated: “And I will set My face against them; out of the fire they come forth, and the fire should devour them” (Ezekiel 15:7). The Torah is likened to fire in the verse: “Is not My word like fire?” (Jeremiah 23:29). The verse in Ezekiel teaches: “Out of the fire they come forth,” referring to those who separate themselves from the fire of Torah; “and the fire should devour them,” i.e., they are consumed by the fire of Gehenna.

כי אתא רב דימי, אמר רבי יונתן: כל הפורש עצמו מדברי תורה ⁠– נופל בגיהנם, שנאמר: ״אדם תועה מדרך השכל, בקהל רפאים ינוח״. ואין רפאים אלא גיהנם ⁠– שנאמר: ״ולא ידע כי רפאים שם, בעמקי שאול קראיה.

When Rav Dimi came from Eretz Yisrael to Babylonia, he said that R' Yonatan says: Anyone who separates himself from the matters of Torah falls into Gehenna. As it is stated: “The man who strays out of the way of understanding should rest in the congregation of the spirits” (Proverbs 21:16). “The way of understanding” is the way of the Torah. And one who departs from the Torah arrives in the place of the spirits, which is nothing other than Gehenna, as it is stated: “But he does not know that the spirits are there; that those whom she has called are in the depths of the netherworld” (Proverbs 9:18).