Allah Most High says,
And if any fail to judge by what Allah hath revealed, they are unbelievers. (AI-Maidah: 44)
And if any fail to judge by what Allah hath revealed, they are wrong-doers. (AI-Maidah: 45)
And if any do fail to judge by what Allah hath revealed, they are those who rebel. (AI-Maidah: 47)
In his Mustadrak, AI-Hakim reported on the authority of Talhah Ibn Ubaid Allah (may Allah be pleased with him) that the Prophet (pbuh) said,
"Verily, Allah never accepts the Prayer of a judge who judges with what Allah has not revealed.” [Hakim, Mustadrak]
AI-Hakim reported also in his Sahih on the authority of Brada, (may Allah be pleased with him) that the Messenger of Allah (pbuh) said, "The judges are of three types: One type will go to Paradise and the remaining two will end up in the fire of Hell. The judge who will go to Paradise is one who understands the truth and judges accordingly. One who judges unjustly after understanding the truth will go to Hell. Likewise, the judge who judges in ignorance also will go to Hell. The Companions then asked, “What is the guilt of the ignorant one?” He (pbuh) replied,
"Accepting the position of judge is his guilt until he gets a profound knowledge.” [Tirmidhi]
On the authority of Abu Hurairah that the Messenger of Allah (pbuh) said,
"Whoever is appointed to be a judge as if he is slaughtered without a knife.” [Tirmidhi]
AI-Fudail Ibn Eyad (may Allah bestow mercy on him) said, 'the judge should spend a day in his job and a day in weeping over his own self."
Muhammad Ibn Wasi (may Allah best our mercy on him) said,
"On the Day of Judgment, the first of men who will be called to account are the judges.”
Aishah (may Allah be pleased with her) said, "I heard the Messenger of Allah say,
"On the Day of Judgment, the just judge would face a great trial that he wishes if he were not appointed to judge between people even in the division of a palm-date.” [Ahmad]
Ali Ibn Abi Talib (may Allah be pleased with him) said, "I heard the Messenger of Allah (pbuh) say,
"On the Day of Judgment, no ruler or judge but be brought before Allah, Exalted and Dignified be He, over the Sirat, then his deeds will be made public. If he was just, Allah will save him. On the other hand, if he was unjust, the Sirat will strongly tremble to the extent that one's organs would be scattered, the distance between each organ would be such and such long and he will fall into Hell-Fire."
Makhul, moreover, said, "If I were to choose between holding the position of a judge and beheading, I would surely prefer beheading over holding this job."
Ayub Al-Sikhtiani further said, "The more knowledge the scholar get, the more their fear of holding the position of a judge increases."
Having told that Shuraih was appointed to be a judge, Al-Thawri commented, "They would corrupt the man."
It was narrated that Malik Ibn Al-Mundhir appointed Muhammad Ibn Wasi, to be the judge of Basra. When Muhammad objected, Malik warned him that he would flog him if he insisted on his objection. On hearing that Muhammad disclosed, "If you do, you will be a tyrannical ruler. However, I prefer humiliation in this world over the torment in the world to come."
Wahb Ibn Munabbih said, "The more just the ruler is, the more blessing on his people Allah will descend."
A worker wrote to Umar Ibn Abd AI-Aziz, "O Umar! The city of Hims has been destroyed and therefore it is in need of rebuilding." Umar (may Allah be pleased with him) replied, "Fortify it with justice and clean its roads from oppression."
However, the scholars of Islam state that the judge should not utter a judgment when he is angry, anxious or nervous. Furthermore, if a man of ignorance or immorality is appointed to be a judge, he should resign and leave the office.
Ascribing Associates To Allah, the Most High (Shirk)
Killing A Human Being
Not Performing The Prayer
Not Paying Zakat
Breaking One's Fast During Ramadan Without An Excuse
Not Performing the Hajj when Able to
Showing Disrespect to One's Parents
Severing the Ties of One's Relatives
Accepting Usurious Gain
Wrong Consuming An Orphan's Property
Lying About The Prophet
Fleeing From The Battlefield
The Leader Who Misleads His Followers, The Tyrant And The Oppressor
Arrogance, Pride, Conceit, Vanity And Haughtiness
Bearing False Witness
Accusing A Woman Of Adultery
Misappropriating Spoils Of War, Muslim Funds Or Zakat
Highwaymen Who Menace The Road
The Engulfing Oath
Taking People's Property Through Falsehood
The Consumption of Haram
The Dishonest Judge
Women Imitating Men And Vice Versa
The Pimp and the one Who Permits His Wife to Fornicate
Marrying Solely To Return To The Previous Husband
Not Freeing Oneself Of All Traces Of Urine
Showing Off In Good Work
Learning Sacred Knowledge For The Sake Of This World, Or Concealing It
Breach of Trust
Reminding Recipients of Ones Charity To Them
Disbelieving In Destiny (qadar)
Listening To People's Private Conversations
The Talebearer Who Stirs Up Enmity Between People
Breaking Promises or Pledges
Believing Fortune Tellers And Astrologers
Wife Rebelling Against Her Husband