R. Zera said in R. Hiyya b. Ashi's name in Rab's name: A man may squeeze a bunch of grapes into a pot [of food], but not into a plate; but [one may squeeze] a fish for its brine even into a plate.
Well and good. But then an argument breaks out about sources:
Now, R. Dimi sat and stated this ruling. Said Abaye to R. Dimi, You recite it in Rab's name, hence it presents no difficulty to you; [but] we recite it in Samuel's name, so it presents a difficulty to us
It does so because Samuel seems to give a contradictory opinion in another source.
R. Dimi responds in a most unusual way:
By God! (Haelohim!) replied he, 'Mine eyes have beheld, and not a stranger': (Job 19:27) I heard it from R. Jeremiah's mouth, and R. Jeremiah from R. Zera, and R. Zera from R. Hiyya b. Ashi, and R. Hiyya b. Ashi from Rab.