Reference for Pesachim 178:13

אזל עריב בהדי רבינא אדאכיל רב הונא בריה דרב יהושע חדא אכיל רבינא תמניא אמר מאה פפי ולא חדא רבינא

Said he to him, There the reason is because they can say to him, 'We accepted you for the purpose of the sacrifice.' He refuted him by [the teaching regarding] 'a meal in common [etc.]', so he divided with him. Then he went and joined bread with Rabina.

Jastrow