A. Yusuf Ali:Translation:
We have sent down to you the Book in truth, that
you mightest judge between men, as guided by Allah.
so be not (used) as an advocate by those who betray
their crust; 621

Muhammad Asad:Translation:
BEHOLD, We have bestowed upon thee from on high this divine writ, setting forth the truth, so that thou may judge between people in accordance with what God has taught thee. 133 Hence, do not contend with those who are false to their trust,
621 The Commentators explain this passage with reference to the case of Ta'imah ibn Ubayraq, who was nominally a Muslim but really a hypocrite, and given to all sorts of wicked deeds. He was suspected of having stolen a set of armour, and when the trail was hot, he planted the stolen property in the house of a Jew, where it was found. The Jew denied the charge and accused Ta'imah, but the sympathies of the Muslim community were with Ta'imah on account of his nominal profession of Islam. The case was brought to the Prophet, who acquitted the Jew according to the strict principle of justice, as "guided by Allah". Attempts were made to prejudice him and deceive him into using his authority to favour Ta'imah. When Ta'imah realized that his punishment was imminent he fled and turned apostate. (R). The general lesson is that the righteous man is faced with all sorts of subtle wiles: the wicked will try to appeal to his highest sympathies and most honourable motives to deceive him and use him as an instrument for defeating justice. He should be careful and cautious, and seek the help of Allah for protection against deception and for firmness in dealing the strictest justice without fear or favour. To do otherwise is to betray a sacred trust; the trustee must defeat all attempts made to mislead him.