Talmud:
> Gentiles are neither to be lifted [out of a well] nor hauled down [into it].
Avodah Zarah, p26b. https://www.sefaria.org/Avodah_Zarah.26b

Shulchan Arukh:
> and those who deny the Torah or Jewish prophecy, there is a mitzvah to remove them. If there is a way to remove them publicly, we would do so. If not, we would use excuses to remove them. How so? If one saw one of them fall into a pit and the ladder is in the pit, he would come and remove the ladder and say he is busy taking his son down from the roof and he will return the ladder, or something similar.
https://www.sefaria.org/Shulchan_Arukh%2C_Choshen_Mishpat.425.5?lang=bi&with=all&lang2=en

Shulchan Arukh:
> Thus, one must not heal them, even for payment, unless there is reason [to save them] on the grounds of [preventing] hatred [of Jews].
https://www.sefaria.org/Shulchan_Arukh%2C_Yoreh_De'ah.158.1?lang=bi&with=all&lang2=en

this jewish belief comes from the 'rabbi and the ladder' story you may have heard before.
and if you scroll up from that part of the talmud (Avodah Zarah p26) it basically reads:
> No! Lies will bring us closer to our father satan than money! Therefore the jew should lie and let the goy die than save him for shekels!