Chagigah 20B

והתניא: הרי שהיו חמריו ופועליו טעונין טהרות, אף על פי שהפליג מהן יותר ממיל ⁠— טהרותיו טהורות. ואם אמר להם: ״לכו ואני אבוא אחריכם״, כיון שנתעלמו עיניו מהן ⁠— טהרותיו טמאות.

But isn’t it taught in a baraita: With regard to one whose donkey drivers and workers, who were amei ha’aretz, were bearing pure food, without touching the pure food itself but only the earthenware vessels containing them, even if he distanced himself from them as they walked by more than a mil, his pure foods are pure. Since the workers are unaware of his departure, he is still considered to be guarding the food in their possession and need not be concerned that they may have touched the pure foods. But if he said to them: Go, and I will follow behind you, then once they are no longer within his eyesight, his pure foods are impure.

מאי שנא רישא ומאי שנא סיפא? אמר רבי יצחק נפחא: רישא במטהר חמריו ופועליו לכך.

The Talmud asks: What is different in the first clause of the baraita, where the food remains pure, and what is different in the latter clause, where the food is impure? R' Yitzḥak Nappaḥa said: The first clause is referring to one who purifies his donkey drivers and workers for this purpose, meaning that he ensured that they immersed and purified themselves beforehand, so that concern for impurity was removed.

אי הכי, סיפא נמי! אין עם הארץ מקפיד על מגע חבירו.

The Talmud questions this: If so, in the latter clause they should also be pure. The Talmud responds: An am ha’aretz is not particular about the contact of his colleague, and therefore there is concern that they might have encountered another am ha’aretz on the way, who touched the produce and thereby rendered it impure.

אי הכי, רישא נמי! בבא להם דרך עקלתון.

The Talmud counters: If so, in the first clause of the baraita there should also be concern that they might have met an am ha’aretz, and despite the employer’s warning to his workers to stay ritually pure, they are not careful with regard to the impurity of another am ha’aretz. The Talmud answers: The first clause is referring to a situation when he comes across them via a circuitous path. Since he is not walking directly behind them but can appear from the sides, they cannot always see him. Consequently, they are concerned that he may return at any moment. Therefore, they are careful not to render themselves ritually impure, and they are also wary of the contact of other amei ha’aretz, although they are not usually particular about the contact of their colleagues.