Halakhah for Nedarim 39:9

אמר רב יוסף הואיל ואמרי רבנן אין נזקקים לו בי דינא דמזדקקי לא עביד שפיר רב אחא בר יעקב אומר משמתינן ליה:

and do not frequent an 'am ha-arez, for eventually he will give you tebalim;<span class="x" onmousemove="('comment',' Tebel, pl. tebalim, produce from which no tithes have been set aside. ');">¹⁶</span> and do not associate with a priest, an 'am ha-arez, for ultimately he will give you <i>terumah</i> to eat;<span class="x" onmousemove="('comment',' According to this reading the exhortation is to a zar. The Ran however reads: 'unclean terumah', which was forbidden even to a priest, in which case the exhortation is to a priest. ');">¹⁷</span>

Tur