The correct way to greet scholars is to greet them with salaam and shake their hand. Many ahaadeeth have been narrated concerning the virtue of these actions. It is also permissible to kiss their heads or hands sometimes, but that should not be taken as a habit or custom, especially if it is done instead of shaking hands.
With regard to embracing, that is permissible when someone comes from a journey or after a long absence, or to express one's deep love for the sake of Allaah and so on.
Muslim (54) narrated that Abu Hurayrah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “By the One in Whose hand is my soul, you will not enter Paradise until you believe, and you will not believe until you love one another. Shall I not tell you something which, if you do it, you will love one another? Spread the greeting of salaam amongst yourselves.”
And it was narrated that Qataadah said: I said to Anas: Did the companions of the Prophet (peace and blessings of Allaah be upon him) shake hands with one another? He said: Yes. Narrated by al-Bukhaari, 5908.
And it was narrated that Anas said: When the companions of the Prophet (peace and blessings of Allaah be upon him) met they would shake hands with one another, and if they came from a journey they would embrace one another.
Narrated by al-Tabaraani in al-Awsat (1/37); classed as saheeh by Shaykh al-Albaani in al-Silsilah al-Saheehah, 2647.
It was narrated from ‘Awn ibn Abi Juhayfah that his father said: When Ja’far came after he had migrated to Abyssinia, the Prophet (peace and blessings of Allaah be upon him) embraced him and kissed him between the eyes.
Narrated by al-Tabaraani in al-Kabeer (2/108); there are many corroborating reports which were mentioned by al-Haafiz ibn Hajar in al-Talkhees al-Habeer, 4/96/ it was classed as saheeh by Shaykh al-Albaani in al-Silsilah al-Saheehah, 2657.
It was narrated that Usaamah ibn Shareek said: We stood up for the Prophet (peace and blessings of Allaah be upon him) and kissed his hand.
Narrated by Abu Bakr ibn al-Muqqari in Juz’ Taqbeel al-Yad, p. 58. Al-Haafiz ibn Hajar said: Its isnaad is qawiy. Fath al-Baari, 11/56
Shaykh Muhammad Naasir al-Deen al-Albaani said:
I say: This indicates that the Sahaabah differentiated between whether a person was present or travelling in the manner in which they greeted him. In the first case (when a person was a resident) they shook hands, and in the second case (when a person had come from travelling) they embraced him. Hence I used to avoid embracing when not travelling. In particular, in the first volume of al-Silsilah (no. 160) I narrated a hadeeth in which the Prophet (peace and blessings of Allaah be upon him) forbade bowing, embracing and kissing. Then when I prepared that volume for reprinting, I re-examined this hadeeth and noticed that the word embracing is not mentioned in the corroborating reports on the basis of which I had classed the hadeeth as qawiy, so I took it out, as will be seen in the new edition in sha Allaah which will be published shortly, praise be to Allaah.
When I realized that it was weak, I felt comfortable about taking it out, praise be to Allaah. In particular I saw that Ibn al-Teehaan al-Ansaari embraced the Prophet (peace and blessings of Allaah be upon him), according to the hadeeth that speaks of the Prophet (peace and blessings of Allaah be upon him) coming out to the house of Ibn al-Teehaan (may Allaah be pleased with him), which is narrated in al-Shamaa’il al-Muhammadiyyah (no. 113, p. 79 – Mukhtasar al-Shamaa’il). But here it indicates that this is permissible sometimes, not that it is to be done always, as if it were a Sunnah, and as is the case with shaking hands, so attention should be paid to that.
I noted that Imam al-Baghawi spoke about the differentiation mentioned above, and I think it will be very useful to quote him here. He (may Allaah have mercy on him) said in Sharh al-Sunnah (12/293), after mentioning the hadeeth of Ja’far and others which may appear to be contradictions:
With regard to the kind of embracing and kissing that is makrooh, it is that which is done by way of flattery and veneration when a person is not travelling. The kind that is permitted is that which is done when bidding farewell and when a person returns from a journey, and when meeting someone after not seeing him for a long time and when there is intense love for the sake of Allaah. What is to be kissed is not the mouth but rather the hand, head and forehead.
It is makrooh to do that when one is not travelling as far as I can see, because one meets people frequently and not everyone deserves that. If a man does that to some people and not to others, those whom he ignores will be upset by that and will think that he is falling short and neglecting their rights. The best greeting is the handshake. End quote.
It should be noted that some of the imams, such as Abu Haneefah and his companion Muhammad, are of the view that embracing is makrooh; al-Tahhaawi narrated this from them, which is opposite to the view of Abu Yoosuf.
Imam Maalik also regarded it as makrooh. In al-Adaab al-Shar’iyyah (2/278) it says:
Maalik regarded it as makrooh to embrace one who comes from a journey and said it is a bid’ah (innovation). He explained the fact that the Prophet (peace and blessings of Allaah be upon him) did that to Ja’far when he came as being a unique case. Sufyaan said to him: You cannot regard it as a unique case without evidence and Maalik fell silent. Al-Qaadi said: The fact that he fell silent indicates that he accepted what Sufyaan said and agreed with him. This is the correct view, so long as there is no evidence that this is a unique case.
We have referred above to the view of Imam al-Baghawi who said that there should be no kissing on the mouth. Shaykh Ibn Muflih explained the reason for that in al-Adaab al-Shar’iyyah (2/275) where he said:
It is makrooh to kiss on the mouth, because it is rarely done out of respect.
And it seems to me that there is another reason, which is that it is not narrated that the salaf did that; if it were good they would have done it before us. How well the poet spoke when he said:
All goodness is in following those who came before and all evil is in the innovations of those who came later.
Al-Silsilah al-Saheeh, vol. 6, section 1 (305-307).
And the Shaykh also said:
With regard to kissing the hand, there are many ahaadeeth and reports concerning that, which when taken together indicate that this is proven from the Messenger of Allaah (peace and blessings of Allaah be upon him). We think that it is permissible to kiss the hand of the scholar if the following conditions are met:
1.That it does not become a custom to such an extent that the scholar habitually stretches out his hand to his students and they habitually seek blessing by kissing his hand, because although the hand of the Prophet (peace and blessings of Allaah be upon him) was kissed, that happened rarely, and such matters cannot be taken as a Sunnah to be done regularly, as is well known from the basic principles of fiqh.
2.That should not make the scholar feel arrogant towards others or admire himself, as happens among many shaykhs nowadays.
3.That should not lead to abandoning any well known Sunnah, such as shaking hands, which is prescribed because of the words and actions of the Prophet (peace and blessings of Allaah be upon him) and is a shar’i means of the sins of those who shake hands being erased, as is narrated in more than one hadeeth. It is not permissible to supercede it or ignore it for another habit which, at best, is permissible.
Al-Silsilah al-Saheehah, 1/302.
With regard to bowing, that is not permissible when meeting anyone, whether he is a scholar or not.
Shaykh al-Islam Ibn Taymiyah said:
With regard to bowing when meeting, it is forbidden as it is narrated in al-Tirmidhi that they asked the Prophet (peace and blessings of Allaah be upon him) about a man who meets his brother and bows to him. He said: “No, because it is not permissible to bow or prostrate to anyone except Allaah, may He be glorified. That may have been done by way of greeting under a law other than ours, as in the story of Yoosuf – “…and they fell down before him prostrate. And he said: “O my father! This is the interpretation of my dream aforetime!” [Yoosuf 12:100].
But in our sharee’ah it is not permissible to prostrate to anyone except Allaah. Indeed it is forbidden to stand as the Persians used to stand for one another – so what about bowing and prostrating? And a slight bow (as opposed to the full bow as in prayer) is also included in this prohibition.
Majmoo’ al-Fataawa, 1/377
And he said:
With regard to lowering one's head before the senior shaykhs or kissing the ground etc, these are matters concerning which there is no dispute among the imams that they are haraam. Indeed, simply bowing to anyone other than Allaah is forbidden. In al-Musnad and elsewhere it is narrated that when Mu’aadh ibn Jabal (may Allaah be pleased with him) came back from Syria he prostrated to the Prophet (peace and blessings of Allaah be upon him) and he said: “What is this, O Mu’aadh?” he said: “O Messenger of Allaah, I saw them in Syria prostrating to their bishops and patriarchs, and they narrated that from their Prophets.” He said, “They are lying, O Mu’aadh. If I were to command anyone to prostrate to anyone else I would have told the women to prostrate to their husbands because of the greatness of their rights over them. O Mu’aadh, do you think that if you pass by my grave you will prostrate?” He said, “No.” He said: “Do not do that.”
In conclusion, standing, sitting, bowing and prostrating are all due to the One God, the Creator of the heavens and the earth. Whatever is a right only for Allaah, no one else can have a share in it, such as swearing by anyone other than Allaah etc.
Majmoo’ al-Fataawa, 27/92, 93.
The scholars of the Standing Committee said:
It is not permissible to bow when greeting or to take off one's shoes for someone.
And they said:
It is not permissible to bow in greeting to a Muslim or to a kaafir, not with the upper part of the body or with the head, because bowing is an act of worship and worship can only be done for Allaah alone.
Shaykh ‘Abd al-‘Azeez ibn Baaz, Shaykh ‘Abd al-Razzaaq ‘Afeefi, Shaykh ‘Abd-Allaah ibn Ghadyaan, Shaykh ‘Abd-Allaah ibn Qa’ood.
Fataawa al-Lajnah al-Daa’imah, 1/233, 234
And Allaah knows best.