Midrash su Genesi 32:31

Whence do we know that litigants in Israel who are involved in litigation against each other must not turn to an idolatrous judge for a decision in their suit, even though they know that he will judge them according to Israel’s laws? Because it is forbidden (for Jews) to argue before them? Scripture states: Which thou shalt set before them. That is, before the children of Israel and not before the Cuthites. For anyone who shuns Israel’s judges and testifies before an idolatrous judge renounces the Holy One, blessed be He, first, and later renounces Israel’s law, as it is said: For their rock is not our Rock, and our enemies’ judge (Deut. 32:31). To what may this be compared? To a patient examined by a doctor. He tells the members of (the patient’s) household: “Give him whatever food he desires, withhold nothing from him.” (Later) he visits another patient and advises his household: “Be careful that he does not eat or drink certain things.” They remonstrate with him, saying, “One patient you permit to eat whatever he wishes, while the other you advise not to eat certain things.” Thereupon he replied: “The first patient will not survive, and that is why I told them not to deny him anything, for whether he eats or not, he will die. However, the other patient will live, and so I advised him to eat only certain things lest his illness be aggravated.” So, too, are the ordinances of the idolaters, as is said: For the statutes of the people were vanity (Jer. 10:3), and it is written elsewhere: Wherefore I gave them also statutes that were not good, and ordinances whereby they should not live (Ezek. 20:25). However, to Israel I gave commandments and desirable statutes, as it is said: Ye shall therefore keep My statutes, and My ordinances, which if a man do, he shall live by them (Lev. 18:5).