Mishnah: If a gentile hires a Jew to perform work with wine used for idolatry—such as to pour it from one vessel to another, or to carry a cask from place to place. And it speaks here specifically about actual Yayin Nesech (wine that has been offered to idol worship). But regarding Stam Yeinam (ordinary gentile wine not known to have been offered), the Gemara raises the question.

If [the non-Jew] hired him to perform another kind of work (not connected with the wine) — then all of his wages are permitted, because even though he is giving him payment, it is not considered as being given on account of the [forbidden] work with the wine, but rather for the other work. And the Gemara explains this matter clearly.

Gemara: [Case of] “Mekudeshet” (betrothal is valid) — this would imply that with things forbidden in benefit (issurei hana’ah), their monetary value is still permitted, and all the more so wages for his labor [should be permitted].

But — since [in the case of Yayin Nesech] its monetary value is seized like that of idolatry — for once it has been libated to idol worship, it becomes like actual idolatry, and its value is prohibited. As it says earlier (Avodah Zarah 54b): “Anything from which one derives [forbidden benefit] is considered like itself.” Therefore, just as its value is forbidden, so too the wages for his labor are forbidden.

Gather for me with it — this is an expression of sale, meaning “gather for me its value in vegetables.”

His wages are forbidden — i.e., to keep them beyond the time of bi’ur (removal) [in the Sabbatical year], but rather they must be disposed of during Shevi’it.

Gather for me vegetables — this is an expression of rental/hire, not of sale, and therefore it does not acquire monetary value that would be seized with the sanctity of Shevi’it.

A case of permission - when it is given as a free gift

As we learned (in a Mishnah) - regarding Ma’aser Sheni