The Oaths are quoted L’Halachah in numerous sources, including but not limited to: Piskei Riaz (Kesuvos 111), Responsa Rivash #110, Responsa Rashbash #2, Megilas Esther on Sefer HaMitzvos of Rambam Ramban (Maamar HaGeulah #1 regarding why all Jews outside of Bavel – the majority of Jews at the time – did not go to Eretz Yisroel at Coresh’s call), Rambam (Igeres Taimon – warning peple not to violate the Oaths or else face grave danger), Maharal (Netzach Yisroel 24) writes that even if the Goyim try to force us to take Eretz Yisroel for ourselves during Golus, we must allow ourselves to be killed rather than take violate the Oaths, as well as other places.
Maharal in Netzach Yisrael:
?? ????? ‘????? ?? ???’ ????? ???? ???? ????? ?? ???, ???? ?????? ?? ???? ?? ???, ?????? ??? ????? ???? ??? ???? ????? ?????. ?? ???? ?? ???, ?? ?? ?? ????? ??? ????? ?????, ?? ??? ?????. ???? ????? ‘????? ?? ???’, ???? ???? ?? ?? ???? ????? ????? ???? ?????? ???, ?? ???? ?????? ??? ???? ????? ???. ??? ?????? ??? ?? ??? ????, ??? ????? ??
The Maharal of Prague’s explains the oaths in his Netzach Yisrael, ch. 24. as saying that these oaths represent absolute prohibitions that one must sacrifice one’s life before violating. In technical terms, these oaths are yehareg ve’al ya’avor. It is better to be martyred than to violate these oaths.