The Prophet (pbuh) said,
"Insulting a Muslim is an act of immorality and fighting him is an act of disbelief." [Bukhari]
He (pbuh) also said, "Cursing a believer is like killing him." [Bukhari]
Muslim narrated in his Sahih the following hadith that states,
"Those who indulge in cursing others will not be intercessors or witnesses on the Day of Judgment."
Another hadith states,
"It is not the character of a believer to indulge in slandering, cursing, or immoral talk." [Tirmidhi]
The Messenger of Allah (pbuh) said,
"When a servant curses something, the curse rises up to the sky, where the doors of the sky shut it out, and then it falls back to earth, where the doors of the earth shut it out. Then it searches right and left and when it does not find anywhere to go it comes back to the thing which was cursed, should it deserve it. If not, it returns upon the person who uttered it." [Abu Dawud]
Umran Ibn Husain said, "While the Prophet (pbuh) was on a journey, there was a woman of the Ansar riding a camel which annoyed her, where upon she cursed it. The Prophet (pbuh) heard this and said,
"Take off what is on its back and release it, for it has been cursed." And it is as if I can still see it now, walking along among the people, no one stopping it." [Muslim]
On the authority of Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah said,
"The worst form of usury is the violation of the personal honor of a Muslim." [Abu Dawud]
Amr Ibn Qays said, "When a man rides on his mount, it says, "O Allah! Make him kind and merciful with me!' should he curse it, it would say, "On my back is the worst disobedient to Allah and His Messenger. May Allah curse him (the man who rides it)!"
Allah Most High says,
Behold! The curse of Allah is on those who do wrong! (Hud: 18)
He also says,
Then let us earnestly pray And invoke the curse of Allah on those who lie. (Al-Imran: 61)
However, many ahadith verify that the Prophet (pbuh) said,
"Allah has cursed the one who takes usury, the one who pays it, the one who writes the contract, and the one who witnesses the contract." [Muslim]
"Allah curses the man who marries a woman after her divorce solely to permit her first husband to remarry her and He curses the first husband as well."
"Allah curses women who wear false hair or arrange it for others, who tattoo or have themselves tattooed, who separate their front teeth for beauty, altering what Allah has created." [Ibn Hibban]
"Allah curses those who make pictures." [Part reported by Bukhari]
"Allah curses him who surreptitiously changes property-line markers." [Bukhari]
"'Allah curses him who curses his parents."
"Allah curses him who insults his mother." [Part reported by Bukhari]
"Allah curses a man who misleads a blind person from the way." [Muslim]
"May Allah curse him who does what Lot's people did." [Ahmad]
"Allah curses him who go to fortune-teller asking him about something, and the one who sodomizes a woman." [Ahmad]
"The woman who loudly lament the dead is cursed."
"He who leads people in Prayer while they detest him is cursed."
"Allah curses a woman who sleeps the night while her husband is angry with her."
"The one who hears muezzin (caller to prayer) say, 'come to Prayer, come to Prosperity', and does not answer the call is cursed." [Tirmidhi]
"Whoever slaughters a sacrifice for the sake of any other than Allah is cursed." [Tirmidhi]
"Allah curses the thief." [Tirmidhi]
"The curse of Allah is upon whoever reviles the Companions of the Prophet (pbuh)." [Tirmidhi]
"The Prophet (pbuh) cursed effeminate men and masculine women."
"The Prophet (pbuh) cursed men who imitate women and women who imitate men."
"The Prophet (pbuh) cursed men who wear women's clothing and women who wear mens." [Tirmidhi]
"He cursed the one who corrupts the relation between a wife and her husband or between servant and his master."
"He cursed the one who has intercourse with a woman during her period or sodomizes a woman."
"He cursed the one who points a blade (or any other weapon) at his brother."
"He cursed him who refuses to give Zakat."
"He cursed him who falsely claims someone is his father, knowing he is not."
"He cursed whoever brands or strikes the face of livestock."
"He cursed the one who intercedes on behalf of a criminal concerning a decree of Allah and the criminal is cursed as well."
"He cursed the wife who goes out from her house without the permission of her husband."
"He cursed the wife who passes the night refusing to satisfy the sexual needs of her husband until she submits to her husband's desire."
"He cursed the one who sodomizes and the one who lets it be done to him."
"Allah has cursed wine, and whoever drinks it, pours it, sells it, buys it, presses it for another, presses it for himself; carries it, accepts its delivery, or ears its price. "
"There are six whom I curse, Allah curses, and who are cursed by every prophet whose supplications are answered: he who denies Allah's Destiny, he who adds anything to Allah's Book, he who rules arrogantly, he who considers what Allah has prohibited to be lawful, he who deems it permissible to treat my family in ways Allah has forbidden (such as insulting or reviling them), and he who abandons my Sunnah (out of disdain for it)."
"He cursed the one who fornicates with his neighbor's wife."
"He curses him who conceals knowledge."
"He curses him who practices masturbation and who fornicates with his mother or his daughter."
"He cursed the one who hoards goods until the price rises."
"He cursed the one who offers a bribe, the one who receives it, and the one who arranges it."
"He cursed the harsh ruler."
"He cursed men and women who refrain from marriage."
"He cursed the one who sodomizes an animal."
It is permissible (but not rewarded by Allah) to curse those who possess blameworthy characteristics, by saying, "Allah curses oppressors," "Allah curses the corrupt," "Allah curses picture-makers," and so forth.
As for cursing a particular person who commits some act of disobedience, such as an oppressor, adulterer, maker of pictures, the thief, or the one who consumes usurious gain; the hadith evidence seems to suggest that it is not unlawful, though Ghazali indicates (and it is the most reliable opinion) that is unlawful unless the person cursed is someone we know has died in a state of unbelief, such as Abu Lahab, Abu Jahl, Pharaoh, Haman, and others like them. This, Ghazali notes, is because "to curse means to distance another from the mercy of Allah Most High, while we do not know how the particular corrupt person or non-Muslim will end his life."
As for those the Prophet (pbuh) personally cursed such as the tribes of Ri'la, Zakwan and Usiah, perhaps it was because he knew they would die in unbelief. Praying that evil befalls a person is similar to cursing, even when against a tyrant, such as saying, 'May Allah not heal him,' 'May Allah not keep him safe,' and similar remarks, all of which are blameworthy (being unlawful, if of a Muslim). And likewise for cursing any animals or inanimate objects whatever, all this is objectionable."
The scholars therefore say, "Whoever curses someone who does not deserve so, let the former modify it by saying, if he deserves to be cursed.'"
It is permissible for one who invites to good and forbids evil to address someone saying, "woe to you', "O you who have wronged his own self" and the like. Provided that he should avoid lying defamation, slander. Besides this, his objective should be admonishing and not insulting people.
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