In the Name of Allah, most Compassionate, most Merciful

The Prophet (P.B.U.H) used to forbid Qil and Qal, idle useless talk or that you talk too much about others.

The disbelievers love to practice Qil and Qal and it is one of their traits.

Quran 9.69. As in the case of those before you: they were mightier than you in power and more flourishing in wealth and children. They had their enjoyment of their portion: and you have of yours (portion) as did those before you; and you indulge in idle talk as they did. They! their works are fruitless in this world and in the hereafter and they will lose (all spiritual good).

The disbelievers 'portion' is that they mocked the true religion and their favorite pastime was to indulge in lies and falsehood. Just as many Muslims today have their 'portion' of mocking the aspects of Islam. This is why the Prophet said, 'You will imitate the traditions (lying and mocking your deen) of those who were before you (Christians and Jews), a hand span for a hand-span and forearm's length for forearm's length, and an arm's length for an arm's length. And even if they enter the den of a lizard, you will also enter it.'

Quran 57:20 Know that the life of this world is only play, and idle talk, and pageantry, and boasting among you...

It is a trait of the disbelievers that they admire this life; they are the most eager to acquire the pleasures of this world, and this life is most dear to them. They think the most important things in life are their women and children, a lot of money, expensive cars and nice homes and land. They love to show off and talk idly about the pleasures of this world while these things all perish eventually. 

23.1-3 The Believers are successful, (are) those who humble themselves in their prayers, who avoid vain talk...

Alternatively it is a trait of the believers that one of the reasons they are the successful is because they avoid boasting and bragging about their belongings and the things of this world, and spend their time worshiping Allah. Khushu` (humbleness and submissiveness) in prayer is only attained by the one who has emptied his heart totally, who does not pay attention to anything else besides it, and who prefers it above all else. At that point it becomes a delight and a joy for eyes.

The Messenger of Allah said, "Fragrance and women have been made dear to me, and Salat was made the joy of my eye." Fragrances and women may have been things liked by the Prophet (P.B.U.H) but he didn't go around boasting, 'hey look at me I have 9 wives and perfumes from all over the world!' The thing that the Prophet (P.B.U.H) loved most was prayer. 

This is totally different to the disbelievers who love to see their worldly possessions and the material is the joy of their eyes. Or the hypocrite Muslims who have little to no khushu` in their prayers because of their love for this world.

A person who loves this world can not attain khushu` due to their mind being on the matters of this world, thus they are the losers. Beware of anyone professing to be a Muslim while talking idly about the material things in this world.

The trait of the believer not to waste time in Qil and Qal is continued in the hereafter as well as the Quran tells us...

19:62 They hear there in (in Paradise) no idle talk, but only Peace! 

Muslims do not abuse others by lying nor do they use swear words. 

Allah's Apostle (peace be upon him), while delivering a sermon one day, said..."The inmates of Hell are of five types: ... (the fourth) the liar and (the fifth) those who are in the habit of abusing people and using obscene and foul language." [Sahih Muslim Hadith 6853 Narrated by Iyad ibn Himar]

Quran 28.55 And when they hear vain talk they turn away there from and say: "To us our deeds and to you yours; peace be to you: we seek not the ignorant." 

Believers do not mix with the people who indulge in such talk. And they do not respond to ugly speech with ugly speech as they never say anything but good words. 

Allah's Apostle said, "Whoever believes in Allah and the Last Day should talk what is good or keep quiet..." [Sahih Al-Bukhari Hadith 8.482 Narrated by Abu Huraira]

Therefore, when someone says something ignorant to annoy you, do not allow it to get the better of your emotions and do not respond to it with obscenities as this is the trait of the disbelievers and you may become used to idle talk and bad words.

Allah's Apostle said, "Whoever can guarantee (the chastity of) what is between his two jaw-bones and what is between his two legs (i.e. his tongue and his private parts), I guarantee Paradise for him." [Sahih Al-Bukhari Hadith 8.481 Narrated by Sahl bin Sad]

Therefore, the benefit of keeping control of our tongues is Paradise! By responding to evil talk with evil talk we are being led astray which is exactly what the disbelievers want.

On the day of Judgment the disbelievers will say, "...but we used to talk vanities with vain talkers." [74.45]

So it is also a trait of the disbelievers that they speak about what they have no knowledge of and every time someone goes astray they go astray with them. So, believers need to be firm in their deen without doubts so that they are not lead astray. One of the ways to do this is to avoid talking about things they don't understand, which can cause them to lie about Allah or the Prophet (P.B.U.H)

A believer wanting to talk about Islam to a disbeliever may feel hurt when the disbeliever rejects and abuses him for saying things that are clearly the truth...

3.186 You shall certainly be tried and tested in your possessions and in your personal selves; and you shall certainly hear much that will grieve you from those who received the Book before you and from those who worship many gods. But if you persevere patiently and guard against evil then that will be a determining factor in all affairs. 

The disbelievers when they hear Quran know it is the truth and this makes them react angrily and say hurtful things. This can upset the believer but we must be patient and guard against responding to such speech with evil speech.

The Holy Prophet (P.B.U.H) said, "Do not take to heart their mockery and jesting; leave them to indulge in their idle talk and foolish conduct if they are bent upon experiencing the disgrace and humiliation of the Resurrection; they will themselves see their evil end."'

Truly those who waste their time talking stupidly about things they don't know will be the dwellers in hellfire.  Believer's job is to warn, not argue.

There are also people going around calling themselves Muslims while in fact they are only pretending to be Muslims in order to destroy the religion.

33.60 Truly if the Hypocrites and those in whose hearts is a disease and those who stir up sedition in the City desist not We shall certainly stir you up against them.

Propaganda was used by hypocrites to scare and lower the moral of the believers to try to make them doubt there religion. Today we see many hypocrites brandishing the 'western version' of Islam in an attempt to confuse the ignorant about their religion for the benefit of the non-Muslims.

The disbelievers waste their time with idle talk about their material items and in telling lies and foul language in order to protect their material items. But, time is precious.

Allah's Apostle said, "Allah said, 'The offspring of Adam abuse the Dahr (Time), and I am the Dahr; in My Hands are the night and the day!'" [Sahih Al-Bukhari Hadith 8.200 Narrated by Abu Huraira]

So how should believers talk to each other without wasting time?

Messenger of Allah said, "No people sit together without mentioning Allah, but they will see that as regret on the Day of Resurrection."

The Prophet, (P.B.U.H) went out to a circle of his Companions and asked, 'What makes you sit here?' They said, 'We are sitting here in order to remember Allah and to praise Him because He guided us to the path of Islam and he conferred favors upon us.' Thereupon he adjured them by Allah and asked if that was the only purpose of their sitting there. 'They said, By Allah, we are sitting here for this purpose only. ' At this the Prophet, peace be upon him, said, 'I am not asking you to take an oath because of any misapprehension against you, but only because Gabriel came to me and informed me that Allah, the Exalted and Glorious, was telling the angels that He is proud of you'." [Muslim]

So when believers sit together even if they have to talk about business or worldly things (without using that as an opportunity to boast, lie, slander, backbite, cursing, using vulgarities or gossip) they should remember Allah and that will be a reward for them. 

Malik related to me that he heard that Isa ibn Maryam used to say, "Do not speak much without the mention of Allah for you will harden your hearts. A hard heart is far from Allah, but you do not know. [Al-Muwatta Hadith 56.8]

If they come together only with the purpose of talking about Allah and learning from each other then Allah will be proud of them and will not harden their hearts.

We must also pay attention to the lectures given by the imam...

The Prophet (P.B.U.H) said, "If he (a man) sits in a place where he can listen (to the sermon) and look (at the imam), and he does not remain silent, he will have the burden of it. If anyone says to his companion sitting besides him to be silent (while the imam is preaching), he is guilty of idle talk. [Sunan of Abu-Dawood Hadith 1046 Narrated by Ali ibn AbuTalib]

So just as discussing Allah will be a benefit to the believer, distracting others who are learning about Allah and Islam is sin. 

It is imperative that believers think before they speak. Gushing forth with anything that comes off the top of our heads is a sure-fire way to say something dumb which will put them in hellfire...

Allah's Apostle said, "A slave of Allah may utter a word without thinking whether it is right or wrong, he may slip down in the Fire as far away a distance equal to that between the east." [Sahih Al-Bukhari Hadith 8.484 Narrated by Abu Huraira]

Quran 24.15 Behold you received it on your tongues and said out of your mouths things of which you had no knowledge; and you thought it to be a light matter while it was most serious in the sight of Allah. 

How terrifying that a simple careless word could be the cause of much misery in the hereafter. 

We should also remember not to waste time idly talking to the disbelievers, even lying to them, unless as a deception of war, or to curse them is not approved of. This is because it leads you astray when you accustom yourself to lying and bad talk.

Malik related to me that he heard that Abdullah ibn Masud used to say, "You must tell the truth. Truthfulness leads to right action. Right action leads to the Garden. Beware of lying. Lying leads to corruption, and corruption leads to the Fire. Don't you see that it is said, 'He speaks the truth and acts rightly,' and, 'He lies and is corrupt.' " [Al-Muwatta Hadith 56.16]

Malik related to me from Yahya ibn Said that Isa ibn Maryam encountered a pig on the road. He said to it, "Go in peace." Somebody asked, "Do you say this to a pig?" Isa said, "I fear lest I accustom my tongue to evil speech." [Al-Muwatta Hadith 56.4]

Although you are right to hate them, don't waste your time cursing the evil disbelievers or gossiping about their deed, rather spend your time remembering Allah. 

The traits of the believer (in regard to speech) is they ...

• are truthful and have the best speech.  
• think before speaking
• do not respond to insults with evil speech
• do not boasting about material things
• avoids vain talk
• remembers Allah in all conversations
• do not spread propaganda that may cause fear and doubts in the believers
• do not mix with the people who indulge in idle talk
• are quiet when learning deen from their imam
• do not use foul language
• talk good or keep quiet