But there are some people who trade in distracting tales to misguide people from Allah’s Way knowing nothing about it and to make a mockery of it. Such people will have a humiliating punishment. (Surah Luqman: 6)
Some people voice their ideas about the things they live through all day long by continuously muttering to themselves. Sometimes something that bothers them, sometimes a subject they think is faulty, sometimes a flawed attitude they observe, sometimes a word they hear uttered may cause such people to express their discomfort about these point without thinking much on it.
Actually, it is of course not wrong for a person to voice something he sees at fault. However for such a talk not to be wrong, the aim to do this should definitely be –for the approval of Allah- 'to correct that mistake'. And if there is a faulty behavior, word or incident in question, then this point should definitely be communicated to people who can solve it. And at the same time, the mistake done should be explained to the other party with the nicest and most wise wording.
In this habit of "grumbling", there is no place for any of those mentioned goals. The aim in this is only to "quell one's anger and rage" by saying everything that comes across his mind. And this, clearly manifests how vain and wrong such a manner is.
For instance; "Who put this here?", "Look at this mess, no one cleaned here for days!", "How noisy they are!", "How many questions are they going to ask?", "See... he did it all wrong again; I have explained it to him so many times!", "He left his surroundings all in a mess!" are among the commonly known sentences for grumbling that are repeated habitually all day long.
Sometimes such people continuously grumble not only about the things others do, but also about the things they live through themselves:
They voice all their negative thoughts about almost every subject about their daily life, while working on one side, with phrases like; “I am so hungry”, “I couldn't sleep at all”, “I am sleepless”, “How am I to do this on time, I have so little time left", "I am too late", "I am very ill", "My head is aching", "How am I to finish this?", " I am exhausted!", " I don't feel like getting up", " I am very cold," "It is too hot", "I have so much work to do now, how am I to do all those on one day?".
The common point of all these talks is, as stated above, never the aim to find a solution for those. The aim is only to voice the discomfort one feels. As a matter of fact, since no precaution is taken for the solution and no attempt is made in this regard, this irritating situation goes on and on. Consequently this person continues to grumble as he is used to do.
However according to the morality of the Qur'an, a person is responsible from everything he sees around him, everything he hears around him and every incident he bears witness to. If there is something wrong going on, it is the responsibility of a Muslim to "correct it or to strive for the correction of it". Consequently, a Muslim's point of view about an irritating situation should be about "coming up with a solution".
Along with that, such people ignore the discomfort that the ones around them, who bear witness to their muttering and grumblings, would feel about this situation. However, to be with someone who complains about almost everything is both spiritually and physically grueling and wearing.
First and foremost, the fact that the state of mind of a person who keeps grumbling is not compliant with the Qur'an and that such a person would actually be living completely by the morality of ignorance, would cause a serious discomfort and oddity for Muslims witnessing these. That is because a grumbling person would give the impression that he had "forgotten that Allah created everything and that there is benefaction and wisdom in every incident, and that everything happens within the scope of destiny and especially for the test of people". Such behavior creates the suspicion that he is unaware of the fact that one should respond to all incidents which seem to be hardship and trouble, which requires one to show patience and selflessness, with the morality of the Qur'an. It of course raises doubt for that person to leave himself spinelessly to the morality of the ignorance, even though he is responsible of living by the morals which requires him "to control his rage when he faces things that might make him angry; to say the best of the words; to preach people around in the best possible way; to command the good and to forbid the wrong."
A Muslim is the person who uses his conscience. He is responsible of fearing from Allah and of behaving according to the morality of the Qur'an at every moment and of saying every word by thinking if it is compliant with the Qur'an or not.
A Muslim knows that the habit of grumbling is not compatible with the morality of a person who believes in Allah, who knows destiny and that this world is a place for 
testing and who is aware of the Hereafter. Grumbling is an unbecoming attitude to nobility of a Muslim and it is indecorum to the awareness and conscience of a Muslim. A Muslim would make good every defect he sees, on his own by his own means, if necessary but nonetheless does not speak in such a complaining manner. No matter how wronged he might appear to be, he never reflects these in a complaining manner. He tries to correct this situation by talking to the related people or by taking the necessary precautions; but never tells about those in the shallow turn of phrase of ignorance. Even if he comes across something irritating, he controls his anger. He never reflects his anger aimlessly just because he feels angry inside. A Muslim knows that that grumbling is not the way of freeing oneself from anger. He is well aware of the fact anger can only be removed by submission to Allah and abiding by the morality of the Qur'an.
Consequently, "grumbling" is one of the most important moral attributes that differentiates the Muslims from the people of society of ignorance. Accordingly, approaching this subject with such point of view and using one's mind, conscience and willpower in the best way, to live by the morality of the Qur'an in the most perfect manner, is a beautiful responsibility faith lays on them.
And say to My servants to speak that which is best. The satan plants animosity between them. The satan was to mankind a clear enemy. (Surat Al-Isra': 53)
