Bava Batra 74 - 80
Rav Yehuda said: All who separate from the words of the Torah are consumed by fire, as is written (in Yechezkel 15:7): And I shall set My countenance against them; from the fire they have emerged, and the fire will devour them.
When Rav Dimi came from Eretz Yisrael to Bavel he said in the name of Rabbi Yochanan: Anyone who separates himself from the words of Torah falls into gehinnom, as it is written (in Mishlei 21:): A person who strays from the path of understanding (the Torah) will rest in the congregation of ‘refaim’ (gehinnom).
Although these two statements sound virtually identical, the Maharsha explains that they refer to two completely different situations, and convey separate messages.
The first teaching refers to two people who were learning together, but then inexplicably ceased learning Torah. At first they were “heating each other up with the fire of Torah” and “no other fire can consume fire”. But if they neglect the importance of Torah study, and interrupt each other from their Torah study, they lose the special protective nature of their Torah study. This will result in their likely falling victim to their inclinations that entice them to transgress the Torah, and be subject to punishment (being consumed by fire of idolatry and the like). The plural wording of the verse in Yechezkel indicates that this message refers to a situation of (at least) two people.
The second teaching, however, is stated in the singular, and is also based on a verse that is in the singular. It refers to an individual who is learning Torah and teaches the effect that his separation from Torah study has on his nature. In this case he separates from Torah study on his own initiative, and not as the result of being persuaded by another Torah student, as in the first case. This case is worse. And as an immediate result of this decision, he is not merely tempted to transgress, but has already substantially lowered his spiritual stature to the point that he has “fallen into gehinnom.”
- Bava Batra 79a