daf bit: Bechorot 31

[cellio]

The g'mara on today's daf takes a side path to teach us about crediting our sources. R. Idi was the attendant of R. Sheshet and heard him teach; R. Idi repeated the teaching in the college but did not credit R. Sheshet. R. Sheshet heard about it and was annoyed, saying "he who has bitten me, a scorpion should bite him". What practical difference did this make to R. Sheshet? As R. Yehudah said in the name of Rav, what does "I will dwell in your tent in both worlds" mean when we can only dwell in one place? This means "may they cite a teaching in my name in this world". For R. Yochanan reported in the name of R. Shimon b. Yochai: when a tradition is cited in a scholar's name in this world, his lips murmur in the grave. (31b)

So teaching someone's teachings provides a sort of immortality, according to the rabbis, and not crediting your sources isn't only a matter of theft.