Yet if you do decide to arbitrate, judge only by what Allah has revealed to you, for that alone is true justice.
The Exalted said:
“Avid listeners to falsehood, voracious consumers of illicit gain. If they come to you, then either judge between them or turn away from them; and if you turn away, they can never harm you in the least. But if you judge, judge between them with equity—for Allah loves those who act justly.” ⦗Qur’an 5:42⦘
He then said:
“How is it that they seek your judgment when they already have the Torah, wherein is Allah’s judgment? Yet after that they turn away, and such people are not believers. Indeed, We sent down the Torah containing guidance and light. By it the prophets who had submitted judged for the Jews, as did the rabbis and scholars, for they were entrusted with the preservation of Allah’s Book and were witnesses over it. So do not fear the people; fear Me. And do not barter My revelations for a paltry price. Whoever does not judge by what Allah has revealed—it is they who are the unbelievers. We prescribed for them in it: a life for a life, an eye for an eye, a nose for a nose, an ear for an ear, a tooth for a tooth, and for wounds an equivalent retaliation. But whoever waives it, that shall be an expiation for him. Whoever does not judge by what Allah has revealed—it is they who are the wrongdoers.” ⦗Qur’an 5:43–45⦘
Here Allah extols the Torah, affirming that it contains His judgment, that He Himself revealed it, and that within it are “guidance and light by which the prophets who had submitted judged for the Jews” ⦗Qur’an 5:44⦘. Immediately after mentioning this He states: “Whoever does not judge by what Allah has revealed—it is they who are the disbelievers.” ⦗Qur’an 5:44⦘