The most important part of the body is the heart as has been mentioned by our noble Prophet Muhammed - SallAllahu 'alaihi wa sallam - in his saying, “Indeed there is a piece of flesh in your body that, if it be sound, then the whole body will be sound and if it be corrupt then the whole body will be corrupt. Indeed it is the heart.” - Sahih al-Bukhari [1/49] & Sahih al-Muslim 
The heart is thus the port where all actions stem, whether good or evil. If the heart is good then the actions will be good and if the heart is corrupt then the actions will be bad. The heart is the place where Allah scans, as the Messenger of Allah - SallAllahu 'alaihi wa sallam - says, “Allah does not look at your bodies nor your faces but he scans your heart and actions.” - Sahih al-Muslim [4/6221]
As for the heart, Allah has commanded us to love Him and His Messenger, to love the righteous people, to love that which Allah loves and to hate all which Allah hates. The tongue acts accordingly, because.... the tongue expresses what is in the heart.
The Tongue Expresses what is in the Heart:
If a person is good, it reflects in their saying. Allah has made it very easy for the tongue to move, and it is not difficult to realize that a person’s tongue moves much more as if compared to the limbs. So if a person is not careful about what he says, even a single saying of his can invalidate his actions. It is for this reason that the whole body warns the tongue saying, “Fear Allah concerning us, for we are (dependant) upon you. If you are upright then we will be upright and if you are corrupt then we will be corrupt.” - Sunan at-Tirmidhi (1912), Mishkaat (4838) and Riyaadh as-Saleheen (2/1521)
And at the same time, the tongue is a great blessing from Allah. If we look at the animals, who are unable to speak, we realize the importance of this great tool of communication.
The gratitude that we should show for this great blessing should include, using it for the obedience to Allah, for reading the Qur'aan, for seeking Knowledge, to enjoin good and forbidding evil. The prohibitions of the tongue are that you do not lie, abuse, use foul language, backbite and slander.
Allah says in the begining of Soorah al-Mumineen, “Indeed successful are the Believers, those who in their prayer have Khushoo’ (fear of Allah) and those who refrain from vain talk.” [Soorah Mumineen : 1-3]
Here Allah mentions that refraining from vain talk is a sign of the successful believers. Allah also mentions refraining from vain talk after he mentions al-Khushoo’. This is because too much talk makes the heart hard. It is not possible to reach the level of Khushoo’ (fear of Allah) unless one refrains from vain talk.
Imaam an-Nawawee - rahimahullah - mentions “Know it is incumbent upon all to guard their tongues from most speech, except a word that has some benefit in it....” - Kitaabul-Adhkaar
And for those who take heed there is a constant reminder in the verse, “Not a word is said except that there is a watcher by him ready to record it.” - [Soorah Qaf (50):18]
The Messenger of Allah, Muhammed - SallAllahu 'alaihi wa sallam - said, “Whoever believes in Allah and the Last Day should speak good or keep silent.”
Imaam ash-Shafiee - rahimahullah - said. “If you wish to speak then it is upon you to think before you speak. If you think there is good in it then speak and if not then do not speak.”
The earlier mentioned Qur'aanic verses, Hadeeth (sayings) of our noble Prophet and advices by the scholars of Islaam are a guide for those searching for salvation against vain talk. So before we talk, should we not ask ourselves....
? Will this saying of mine please Allah?
? Will this saying of mine bring me closer to Allah?
? Does this saying earn with it obedience to Allah?
If yes, then speak, otherwise one should keep quiet.
Guarding your tongue from all Haaram
The Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “Guard your tongue, stay in your homes and weep over your sins.” - Related by Ibn Mubarak in az-Zuhd (no.134), Musnad Ahmed bin Hambal (5/259), Sunan at-Tirmidhi (2531) and authenticated by al-Albaanee in as-Saheehah (no.890)
Also the Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “Most of the sins of the children of Aadam are from the tongue.” - At-Tabaraanee (3/87/1-2). Authenticated by al-Haafidh al-Mundhiri in al-Targheeb (4/8)
Narrated by Mughira bin Shu’ba - radiAllahu' anhu - : The Prophet - SallAllahu 'alaihi wa sallam - said,
“Allah has forbidden for you:(1) to be undutiful to your mothers, (2) to bury your daughters alive, (3) not to pay the rights of the poor and others (i.e. charity) and (4) to beg of men. And Allah has hated for you: (1) Qil and Qal (sinful and useless talk, like backbiting or that one talks too much about others), (2) to ask too many questions (in disputed religious matters, etc.), (3) to waste your wealth (by extravagance with lack of wisdom and thinking).” - Sahih al-Bukhari [3:591]
Abu Moosa al-Asharee - radiAllahu' anhu - said, “O Messenger of Allah, which of the Muslims are better?” The Messenger of Allah said, “Those who do not harm the Muslims with their tongues and hands.” - Saheeh al-Bukhari (1/10) and Saheeh al-Muslim (1/64)
Sahl ibn Sa’ad - radiAllahu' anhu - reported that the Messenger of Allah said, “Whoever guards what is between his jaws and legs. I shall guarantee him paradise.” - Saheeh al-Bukhari (8/481). A similar narration can be found in Muwatta of Imam Malik (56/11) and Sunan at-Tirmidhi.
When the Companion of the Prophet, Mu’adh ibn Jabal - radiAllahu' anhu - asked the Prophet - SallAllahu 'alaihi wa sallam - about that which would entitle him to enter Paradise and save him from the hell-fire, he - SallAllahu 'alaihi wa sallam - mentioned the pillars of Islam and informed Mu’adh of the importance of the night prayers and of Jihaad. He - SallAllahu 'alaihi wa sallam - then said, “Should I not inform you of the sheet anchor of all this?”, and then took hold of his tongue and said, “Exercise restraint on it.”. Mu’adh - radiAllahu' anhu - enquired, “O Messenger of Allah, will we be held responsible for what we say with it?” Thereupon, the Messenger of Allah said, “Mu’adh, will anything else besides (irresponsible) talk cause the people to be thrown in the Hell-Fire upon their faces?” - Sunan at-Tirmidhi and Riyaadh as-Saaliheen (2/1522)
Most of the people who will enter the fire, will do so due to their tongues
So a Muslim must beware and learn to imprison the tongue from vain talk, for the Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “Every saying of the children of Aadam is cursed, expept for the enjoining good and forbidding the evil or for the remembrance of Allah.” - Sunan at-Tirmidhi
And “The world and all that it contains is cursed, except for the remembrance of Allah and what supports it,and a scholar and a student.” - Sunan Ibn Majah (no.4112) and and authenticated by Sheikh al-Albani in Saheehul-Jaami’ (no.3414)
Abu Hurairah - radiAllahu' anhu - reports on the authority of the Prophet - SallAllahu 'alaihi wa sallam - that, “From the good Islaam of a man, is that he leaves that which does not benefit him.” - Musnad Ahmed bin Hambal (4/132), Sunan at-Tirmidhi, Sunan Ibn Majah, al-Baihaqi in Shu’ab al-Imaan
Imaam Ahmad - rahimahullaah - mentioned in his Musnad on the authority of Anas radiAllahu ‘anhu who relates that the Prophet - SallAllahu 'alaihi wa sallam - said’ The eemaan of Allah’s servant will not be upright until his heart is upright and his heart will not be upright until his tongue is upright.” - Also mentioned in al-Mundhiri (3/234) and al-Iraqee in al-Ihya (8/1539)
One saying ! ! Subhan Allah:
Abu Hurairah - radiAllahu' anhu - said that he heard the Messenger say, “Indeed a servant (worshipper of Allah) may say a word which he doesn’t realize and it will make him fall into the fire further than the East and the West.”
Abu Hurairah - radiAllahu' anhu - also reported that the Prophet SallAllahu alaihi wa sallam said, “Indeed a servant may say a word from which Allah’s pleasure is gained and the servant does not realize it, Allah will raise him up levels. Indeed a servant may say a word from which Allah’s displeasure is gained and he does not realize it, Allah will put him in Jahanam due to it.” - Saheeh al-Bukhari (8/485), Al-Muwatta (56/6) and in Saheehul-Jaami’ of al-Albaani
Imaam Ahmed - rahimahullaah - along with at-Tirmidhi, an-Nasaai and Ibn Majah record a Hadeeth on the authority of the Sahabee, Fujani - radiAllahu' anhu - who said, “O Messenger of Allah tell me something that I may be firm upon?”. He - SallAllahu 'alaihi wa sallam - answered, “Say, My Lord is Allah and then be upright concerning it.” He asked, “What is the thing that you fear for most.” The Messenger of Allah - SallAllahu 'alaihi wa sallam - took hold of his tongue and said, “This!”. - Musnad Ahmed bin Hambal, Sunan an-Nasaai, Sunan Ibn Majah and Sunan at-Tirmidhi
Allah says in the Qur'aan, “Do not backbite each other, would any of you wish to eat the flesh of your dead brother, no rather you hate it!! [Soorah Hujarat :12]
The Messenger of Allah once asked his Companions, “Do you know what is backbiting?” They said, “Allah and His Messenger know best.”. He - SallAllahu 'alaihi wa sallam - said, “To mention about your brother that which he hates.” They said, “If that we see about our brother is true?” He - SallAllahu 'alaihi wa sallam - said, “If there is in him what you say about him then that is backbiting, and if you say of him that which is not true then you have slandered him.” - Saheeh al-Muslim (4/6265), Sunan Abu Dawood (3/4856) and al-Muwatta (56/10)
The Prophet - SallAllahu 'alaihi wa sallam - vigorously opposed all aspects of backbiting, even when it appeared in his own family. For example, once a woman visited Aaisha - radiAllahu' anha - and when the woman got up to leave, Aaisha made a sign with her hand indicating to the Prophet - SallAllahu 'alaihi wa sallam - that the woman was short of stature. The Prophet immediately chastised her, saying “You have backbitten!” and in another narration, “You have said a saying that if mixed with the sea it would change its color.” - Mentioned in Ibn Jareer in Tafseer al-Qur'aan al-Adheem, vol.4, p.328 (30) and Sunan Abu Dawood (3/4857)
Abu Bakra - radiAllahu' anhu - reports that the Messenger of Allah - SallAllahu 'alaihi wa sallam - said, in his khutbah on the day of Nahr, “Indeed the blood, property and honor are sacred to you, like the sacredness of this day (‘arafah), like the sacredness of this place, like the sacredness of this month; Have I conveyed the message?” - Saheeh al-Bukhari (1/105) and Saheeh al-Muslim (2/2803) and part of a lengthy narration
And by Allah he - SallAllahu 'alaihi wa sallam - has conveyed the message, so guard the right of the Believers!
Allah says in the Qur'aan, “Woe to every slanderer and backbiter.” [Soorah Humaza:1]
The Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “The Gossip-monger will not enter paradise.” [Saheeh al-Bukhari (8/82), Saheeh al-Muslim (1/187) and Musnad Ahmed bin Hambal]
The Messenger - SallAllahu 'alaihi wa sallam - passed by two graves and said, “They are being punished. As regards one of them then he used to go around gossip-mongering and as regards the other then he was not careful while urinating.” - Saheeh al-Bukhari (1/215) and Saheeh al-Muslim (1/575)
On the authority of Saeed ibn Zayid that the Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “Indeed the lowest form of usury is to prolong the speech about the honor of a Muslim without justice.” - Sunan Abu Dawood (3/4858)
Overcoming the evil habit of backbiting
Firstly, as Imaam an-Nawawee - rahimahullaah - said that one should remember the punishment of Allah. And remember that Allah is the Lord of the heavens and the earth. He is the One, aware of ever saying, at every time. Then if one remembers this, then it is only natural that one will be modest and shy in this aspect. We need to realize that when one of us is hurt, when something wrong is said about the creation, then what about the Creator, who is the All-Seeing and All-Hearing.
Secondly, we should reflect on the Qur'aanic verse, “Do not backbite each other, would any of you wish to eat the flesh of your dead brother, no rather you hate it!!” [Soorah Hujarat :12]
And we surely hate even the thought of it.
Thirdly, fear that your own faults would be revealed, as the Messenger of Allah - SallAllahu 'alaihi wa sallam - said,
“O you who believe with your tongues, yet eeman has not entered your hearts. Do not backbite the Muslims, nor follow their faults. For he who follows others faults then Allah will declare (disclose) his faults and he whom Allah reveals his faults, then Allah disgraces him in his own house.” - Sunan Abu Dawood (3/4862) and and authenticated by Sheikh al-Albani in Saheeh Jaami’ Sagheer
Fourthly, take the advice of the pious scholars of Islaam, among them ….
Umer ibn Khattab - radiAllahu' anhu - who said, “Be careful from remembering people for it is an illness and be in the remembrance of Allah for it is a medicine.”
A man came to al-Hasan al-Basri - rahimahullaah - and said that, he heard that al-Hassan al-Basri had backbitten him. Upon this he - rahimahullaah - said, “Who are you that I may give you my rewards?”
Fifth, and the most important thing to keep in mind is that there is a great reward to refrain from backbiting, as the Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “Whoever protects the honor of his brother in his absence, Allah will protect his face from the Fire on the Day of Judgment.” - Sunan at-Tirmidhi and and authenticated by Sheikh al-Albani in Saheeh Sunan at-Tirmidhi (2/1575)
Exceptions to Backbiting
There are few exceptions to backbiting, that the scholars have classified, among them …..
• Oppression: If one has been harmed or one’s property has been unlawfully taken away by another, and this person goes to the ruler or judge in order to seek justice, this is not backbiting.
• Changing the Munkar: If one finds a person involved in evil actions or innovations, and one is unable to correct his Munkar. It is allowed to seek the help of a more knowledgeable person, even if it mean defining the Munkar of the evil-doer or innovator.
• Seeking a Fatwa (religious verdict): For example, there is a dispute between a husband and his wife, and if either of them seek the advice of a religious scholar, then this situation is exempt from backbiting.
• Warning a Muslim from evil: For example, if a fellow Muslim is going to do a business with an dishonest person or if a Muslim is unaware that the person to whom he is marrying his daughter to, is an unreligious person; then to advice and guide him is exempt from backbiting.
• Advising against innovators and sinners: If a innovator is openly involved in spreading his innovative beliefs or a sinner remorselessly declares his sin and is thus being a bad example for others; then warning others against him is allowed. But if he commits a sin secretly and as such harms just himself, to openly declare his sins is still strictly prohibitted.
The Messenger of Allah - SallAllahu 'alaihi wa sallam - said, “Do not nurse a grudge (against a Muslim) and do not outbid him for raising the price and do not nurse aversion (strong dislike) or enmity and do not enter into a transaction when others have entered into that transaction and be as fellow-brothers and servants of Allah. A Muslim is the brother of another, he neither betrays (or deceives him), nor humiliates him, nor looks down upon him. Piety is here (and while saying so) he pointed towards his chest three times. All things of a Muslims are inviolable for his brother in faith, his blood, his wealth and his honor.” - Saheeh al-Muslim (4/6219), part of the wording being that of Sunan Abu Dawood (3/4864)
He - SallAllahu 'alaihi wa sallam - also said, “No (Muslim) man will desert a man who is a Muslim in a place where his respect may be violated and his honor aspersed without Allah deserting him in a place where he wishes help; and no (Muslim) man who will help a Muslim in a place where is honor may be aspersed and his respect violated without Allah helping him in a place where he wishes his help.” - Sunan Abu Dawood (3/4866) and and authenticated by Sheikh al-Albani in Saheeh Jaami’ Sagheer