In his letter of commission to Abū Mūsa al-`Ash`arī, `Umar Ibn Khattāb has provided a comprehensive account of the conditions of passing judgement. It explains the rule of conduct associated with appointment to the office of judge. After the necessary salutations1, he says:
Adjudication is a firm religious obligation and a practice2 that must be upheld and followed. Use your understanding, therefore, when a matter is brought before you, for speaking the truth without discernment is of no use. Treat people equally in the way you attend to them; administer justice, and hold court so that a nobleman may not expect you to be partial to him and a weak man may not despair of your justice. Testimony is for the plaintiff to bring and the oath is for the defendant to take. Effecting reconciliation among Muslims is permissible, so long as a reconciliation does not turn unlawful into lawful and lawful into unlawful. If you decided a case yesterday and were to give it a second thought today, and were to be guided to the right decision this time, let not your previous judgement prevent you from accepting the truth, for the truth is eternal3 and is not invalidated by anything, and to return to the truth is better than to persist in error. Use your understanding -- do use your understanding when you are not sure about a matter not found in the Book of God, may He be exalted, or in the Sunnah of His Prophet (sws). Acquire a good knowledge of like and similar cases, and judge matters by analogy with others. If a person claims a missing right or asserts that he is in possession of evidence, appoint a time-limit for him to reach. If he presents evidence, give him his right, otherwise decide against him, for this is most conducive to the dispelling of doubt and the removal of confusion. Muslims are trustworthy4 with regard to the testimony they give about one another -- with the exception of one who has been flogged in connection with a prescribed punishment, is known to have borne false witness, or is of suspicious clientship or lineage -- for God has forgiven on account of oaths and warded off punishment on account of evidence. Take care that you do not become impatient, annoyed, or fretful with the contending parties. For truth and right, when placed where they belong, result in a great reward from God and in one's earning of a good name. Peace be with you!
(Translated by Dr Mustansir Mir)
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1. After the necessary salutations: Arabic : ammā ba`d.
2. The Arabic word is Sunnah, which, although may be interpreted as the practice of the Prophet (sws), here seems to mean past practice in general.
3. eternal: The Arabic word is qadīm. One cannot be absolutely sure that `Umar (rta) is using the word in its technical theological sense, which is probably of later provenance. The basic meaning of "prior" may be intended, the word thus implying that truth comes first and has priority over everything else.
4. Muslims are trustworthy: ie, they are presumed to be trustworthy.