Avodah Zarah 4:12-5:1

Avodah Zara 4:12

Let’s say that a Jew makes kosher wine for a non-Jew. He leaves it in the non-Jew’s domain and the non-Jew writes him a receipt saying that the Jew paid for the wine (even though money may not have yet changed hands). In such a case, the wine is permitted. But what if the Jew wants to take the wine away and the non-Jew does not allow it until he has actually been paid? This once happened in Beit Sheian and the Sages prohibited the wine (because the wine is still considered as belonging to its non-Jewish owner).

Avodah Zara 5:1

If a non-Jew hires a Jew to work with him on non-Jewish wine, the Jew’s wages are prohibited. If he hired him to perform other work then his wages are permitted even if he had the Jew move a barrel of non-Jewish wine from one place to another. If a non-Jew rents a Jew’s donkey to transport non-Jewish wine, the rental fee is prohibited; if he rented it to sit on then the fee is permitted even if he also rested his jug on the donkey.