Marwan al-Asfar said

When 'Umar b. al-Khattab sent out his governors he laid on them the condition that they should not ride a horse not of Arabian breed,* or eat white bread, or wear fine clothing, or shut their gates against the needs of the people, telling them that if they did any of these things punishment would befall them. Then he would accompany them some distance. Baihaqi transmitted in Shuab al iman. * Birdhaun. This word is used of a horse of poor breed, a horse not of Arab breed, or more specifically a Turkish horse. It is suggested that the reason for the wording is to warn governors against riding horses, this being a sign of pride. Prohibiting a breed considered second-rate makes it obvious that to ride horses of the best Arab breed would be even a greater sign of pride.

Abu Bakra told that he heard Allah's Messenger ﷺ say, “No judge must give judgment between two people when he is angry.” (Bukhari and Muslim.)

‘Abdallah b. ‘Amr and Abu Huraira reportad Allah's Messenger ﷺ as saying, “When a judge gives a decision having tried his best to decide correctly and is right, he will have a double reward; and when he gives a decision having tried his best to decide correctly and is wrong, he will have a single reward.” (Bukhari and Muslim.)

Abu Huraira reported Allah's Messenger ﷺ as saying, “He who has been appointed a qadi among the people has been killed without a knife.”* Ahmad, Tirmidhi, Abu Dawud and Ibn Majah transmitted it. *This phrase has troubled commentators. Perhaps the best explanation is that he will have reason to repent of his manner of life, for there are many traditions which express disapproval of undertaking such an office. A somewhat ingenious explanation is that his evil characteristics must be cut away, this being a kind of slaughter.

Anas reported Allah's Messenger ﷺ as saying, “If anyone desires and asks for the office of qadi he will be left to his own devices, but if anyone is forced to accept it Allah will send down an angle who will direct him aright.” Tirmidhi, Abu Dawud and Ibn Majah transmitted it.

Buraida reported Allah's Messenger ﷺ as saying, "Qadis are of three types, one of whom will go to paradise and two to hell. The one who will go to paradise is a man who knows what is right and gives judgment accordingly; but a man who knows what is right and acts tyrannically in his judgment will go to hell, and a man who gives judgment for people when he is ignorant will go to hell.” Abu Dawud and Ibn Majah transmitted it.

Abu Huraira reported Allah's Messenger ﷺ as saying, “If anyone seeks the office of qadi among Muslims till he gets it and his justice prevails over his tyranny, he will go to paradise; but the man whose tyranny prevails over his justice will go to hell." Abu Dawud transmitted it.

Mu'adh b. Jabal told that when Allah's Messenger ﷺ sent him to the Yemen he asked him how he would judge when the occasion arose, and he replied that he would judge in accordance with Allah’s Book. He asked what he would do if he could not find guidance in Allah’s Book, and he replied that he would act in accordance with Allah's Messenger ﷺ’s sunnah. He asked what he would do if he could find no guidance in Allah's Messenger ﷺ’s sunnah, and he replied that he would do his best to form an opinion and spare no pains. Allah's Messenger ﷺ then tapped him on the breast and said, “Praise be to Allah who has disposed His Messenger’s Messenger to something with which Allah's Messenger ﷺ is pleased!" Tirmidhi, Abu Dawud and Darimi transmitted it.

‘Ali said

‘Abdallah b. Mas'ud reported Allah's Messenger ﷺ as saying, “No judge who pronounces judgment among men will fail to come on the day of resurrection with an angel holding the back of his neck. He* will then raise his head to heaven, and if Allah gives orders to cast him down, he will cast him into an abyss forty years deep." Ahmad, Ibn Majah, and Baihaqi in Shu'ab al-lman transmitted it. *i.e. the angel.