First: because of the authentic hadith that the Prophet ﷺ cursed the briber and the one who accepts the bribe (1). Cursing means being cast out and driven away from the mercy of Allah, which indicates that bribery is among the major sins.
Second: because it corrupts people’s character. If people’s cases are decided according to bribes, they become corrupt and begin boasting of who can offer the larger bribe. If a litigant is ruled in favor of when he gives one thousand, but is not ruled in favor of when he gives eight hundred, he will give one thousand. And if he thinks that his opponent will give one thousand, he will give two thousand. Thus people become corrupt.
Third: because it leads to altering the judgment of Allah. By its very nature, the soul is prone to partiality and inclined toward whoever treats it kindly. Thus, when the judge is given a bribe, he judges by other than what Allah has revealed, thereby altering the judgment of Allah.
Fourth: because it involves wrongdoing and injustice. If the judge rules in favor of the briber against his opponent without right, he has wronged the opponent. There is no doubt that wrongdoing will be darknesses on the Day of Resurrection, and that injustice is among the causes of widespread afflictions, such as drought and the like.
Fifth: because it entails consuming wealth unlawfully, or enabling the unlawful consumption of