one can say an excuse to him, such as: My son is standing on the roof and I must go use this ladder to help him down from the roof. Alternatively, he can say to him: A time has been appointed for me to appear in the courthouse [bei davar] and I must attend to this matter. Since the Jew can provide a legitimate excuse for refusing to aid the gentile, there is no need to extract him from the pit.

Avodah Zarah 26a:16

https://en.wikiquote.org/wiki/Talmudic_views_on_gentiles