Etiquette of Giving Advice in Islam
Question

What are the guidelines on how to give advice in Islam? Should it be done privately or in front of other people? Who is qualified to do that?
Praise be to Allah.Virtues of giving advice in Islam
Giving sincere advice is one of the prominent characteristics of Islamic brotherhood; it is part of perfect faith and Ihsan, for a Muslim’s faith cannot be perfect until he loves for his brother what he loves for himself, and until he hates for his brother what he hates for himself. This forms the motive for giving sincere advice.
Al-Bukhari (57) and Muslim (56) narrated that Jarir ibn `Abdullah (may Allah be pleased with him) said: I gave my oath of allegiance to the Messenger of Allah (blessings and peace of Allah be upon him), pledging to establish regular prayer, pay Zakah and be sincere towards every Muslim.
Muslim (55) narrated from Tamim Ad-Dari (may Allah be pleased with him) that the Prophet (blessings and peace of Allah be upon him) said: “Religion is sincerity.” We said: To whom? He said: “To Allah, to His Book, to His Messenger, and to the leaders of the Muslims and their common folk.”
Ibn Al-Athir (may Allah have mercy on him) said:
“Sincerity towards the common folk of the Muslims means: guiding them to that which is in their best interests.” (An-Nihayah, 5/142)
Etiquette of giving advice in Islam
There is a general etiquette for giving sincere advice to which the one who is compassionate towards the Muslims should adhere. This includes the following:

His motive for giving advice should be love of good for his brother and hating for anything bad to befall him. 

Ibn Rajab (may Allah have mercy on him) said:
“With regard to giving sincere advice to the Muslims, [the one who wishes to do that] should love for them what he loves for himself, hate for them what he hates for himself, feel compassion for them, show mercy to their young ones, show respect to their elders, and share their grief and their joy, even if that is detrimental to his worldly interests, such as loving for prices to be dropped for them, even if that causes him to lose some profits on what he sells of trade goods. By the same token, he should hate everything that could cause them harm. He should love what is good for them, and hope for harmony to exist among them and for them to continue enjoying the blessings of Allah. He should pray that they always prevail against their enemies and that all harm be warded off from them. Abu `Amr ibn As-Salah said: Nasihah (sincerity, sincere advice) is a comprehensive word which means that the one who is sincere should want all kinds of good for the one to whom advice is offered, and should try to achieve that for him. (Jami` Al-`Uloom wa’l-Hikam, p. 80)

He should be sincere when giving advice , seeking thereby to please Allah. He should not intend thereby to prove his superiority over his brother.


That advice should be free of any element of deceit or betrayal. 

Shaykh Ibn Baz (may Allah have mercy on him) said: 
“Sincerity means being truthful and honest, with no element of deceit or betrayal. The Muslim, because of his great loyalty and love towards his brother, is sincere towards him and advises him to do all that will benefit him and that he thinks is pure, with no element of insincerity or deceit. Hence the Arabs say Dhahab Nasih [from the same root as Nasihah], meaning pure gold that is free of any element of cheating. And they say `Asal Nasih (pure honey), meaning honey that is free of beeswax or any element of cheating.” (Majmu` Fatawa Ibn Baz, 5/90)

He should not intend when giving advice to shame his brother or put him down.

Ibn Rajab (may Allah have mercy on him) wrote an essay on this topic entitled Al-Farq Bayna An-Nasihah wat-Ta`yir (The difference between sincere advice and shaming).

The advice should be given in a spirit of brotherhood and friendship, with no element of rebuke or harshness. Allah, may He be Exalted, says (interpretation of the meaning):

“Invite to the way of your Lord with wisdom and good instruction, and argue with them in a way that is best.” [An-Nahl 16:125]

It should be done on the basis of knowledge and clear proof. 

As-Sa`di (may Allah have mercy on him) said: 
“Wisdom dictates that giving advice to others should be done on the basis of knowledge, not ignorance, and that one should start with that which is more important, then that which is less important, and with that which is easy to explain and understand, and that which is more likely to be accepted. The advice should be given in a kind and gentle manner. If the person to whom the advice is given pays heed to this approach, which is based on wisdom, all well and good; otherwise we should move on to exhorting him with good instruction, which means enjoining what is right and forbidding what is wrong, accompanied by mention of the reward from Allah for doing good and the punishment for doing wrong. If the person to whom that is addressed believes that what he is doing is sound and correct, or he calls people to falsehood, then we should argue (debate) with him in a way that is best, which means debating with him in ways that are based on rational arguments and religious texts, which includes quoting evidence that he regards as sound and valid, for that is more likely to lead to a positive response. The debate should not lead to dispute or trading of insults, for that would defeat the purpose and serve no interest; rather the aim of the debate is to guide people to the truth, not merely to prove the other side wrong, and so on. (Tafsir As-Sa`di (p. 452)

The advice should be given privately, not out loud in front of people, unless doing so serves a clear interest that outweighs any negative consequences. 

Ibn Rajab (may Allah have mercy on him) said:
“When the early generations wanted to advise someone, they would exhort him in private, to the extent that one of them said: Whoever exhorts his brother one-to-one, that is sincere advice (Nasihah), whoever exhorts him in front of people is shaming him. Al-Fudayl said: The believer conceals his brother’s faults and gives him advice in private, whereas the evildoer exposes his faults and shames him.” (Jami` Al-`Ulum wal Hikam, 1/236)
Ibn Hazm (may Allah have mercy on him) said: 
“If you give advice, then give advice in private, not in public, and by hinting, not by speaking bluntly, unless the person to whom advice is given will not understand hints, in which case there is no option but to speak bluntly.… If you go beyond these guidelines, then you are wronging him and are not being sincere in your advice.” (Al-Akhlaq was Siyar, p. 45)
However, if there is a scenario where giving advice openly clearly serves the greater interest, then there is nothing wrong with giving advice openly, such as correcting one who made a mistake in matters of belief (`Aqidah) in front of people, lest people be deceived by what he said and follow him in his mistake. Another example is denouncing someone who tells people that Riba (usury) is permissible, or spreads Bid`ah (innovation) and immorality among people. In such cases giving advice in public is prescribed, and may even be obligatory, because of the greater interest that is served thereby, and so as to ward off harm that is likely to occur.
Ibn Rajab (may Allah have mercy on him) said:
“If the aim is no more than highlighting the truth of the matter, so that people will not be deceived by the wrong notions uttered by that person, then undoubtedly he (the one who seeks to give advice) will be rewarded for his intention, and on the basis of his intention he will be regarded as being sincere towards Allah, His Messenger, the leaders of the Muslims and their common folk.” (Al-Farq Bayna An-Nasihah wat Ta`yir, p. 7)

The one who seeks to give sincere advice should choose the best words and phrases, deal gently with the person who he is advising, and speak kindly to him.
The one who seeks to give advice should bear with patience any harm that may result because of his advice.
He should respect confidentiality and conceal the faults of his fellow Muslim, and not speak ill of him to others. The giver of sincere advice is gentle and compassionate, loves good and seeks to conceal people’s faults.
He should verify the facts before offering advice, and not act on the basis of assumption or conjecture, so that he will not be accusing his brother of something that he did not do.
He should choose the appropriate time to give advice. Ibn Mas`ud (may Allah be pleased with him) said: People’s energy fluctuates; sometimes they are focused and receptive, and sometimes they lack energy and are not receptive. So approach people when they are energetic and receptive, and let them be when they are lacking energy and focus. (Narrated by Ibn Al-Mubarak in Az-Zuhd, 1331)
He should practice what he preaches, doing what he enjoins people to do and refraining from that which he forbids them to do. Allah, may He be Exalted, said, rebuking the Children of Israel for the contradiction between their words and deeds (interpretation of the meaning):

“Do you order righteousness of the people and forget yourselves while you recite the Scripture? Then will you not reason?” [Al-Baqarah 2:44]
There is a stern warning to the one who tells people to do what is right when he does not do it himself, and forbids them to do what is wrong when he does it himself.
And Allah knows best.