Some Muslims are of the view that one can not initiate or say Salaam to a non-Muslim. They base their argument on the Hadith of the Prophet (p): “Do not initiate the Jews and the Christians with the greeting of Salaam… ”(Muslim).
“Assalamu Alaykum” means more than just “Good morning” or “Good afternoon”. It means you are extending not only your wishes for Allah’s peace to be upon the person, but also you are extending your own guarantee of peace and security, which you are expected to observe towards every Muslim. In the case of a non-Muslim you may not know whether he wishes you well or not.
Therefore according to a Hadith in Bukhari and Muslim, Anas reported God’s Messenger as saying: “When the people of the Book salute you say: ‘The same to you’.” This is a perfectly polite and reasonable response. A Muslim is not on the other hand to abuse a non-Muslim, even if he abuses you, in accordance with another Hadith in which Aisha related that some Jews asked permission to come in to see the Prophet (p) and said, “Death (i.e. Sām, not salām) be upon you.” Aisha retorted “No, but upon you be death and a curse”. The Prophet responded “God is kind, Aisha, and likes kindness in everything.” She asked if he had not heard what they said, and he replied that he had responded with “and upon you”. (Bukhari and Muslim)
However, if there is a mixed group or even one Muslim in a group of non-Muslims, the salam may be used in accordance with another Hadith in which Usama b. Zaid related that the Messenger of God passed a mixed company of Muslims, polytheists who worshipped idols and Jews and gave them a salutation of peace (Bukhari and Muslim).
There is nevertheless another perspective on this subject, based on several verses of the Qur’an and another Hadith.
According to this Hadith in Bukhari and Muslim the Prophet (p) said: “Say Salam to those you know and those you don’t know”. This would imply that there is no need to enquire or guess at the religion of a person before saying salaam. (In the modern context it is not always possible to identify who is a Muslim from his dress or appearance.)
Secondly those who hold this view regard the Hadith about Aisha and the Jews as relating to a particular instance of hostility leading to Aisha’s anger, which the Prophet diffused by telling her he had responded “wa alaik”. This is in accordance with the Qur’anic principle that one may retaliate against injury but not exceed the harm one has received. However this same verse which permits retaliation (Qur’an 5:45) emphasises the superiority of forgiveness. This is repeated in the words of Qur’an 42:40: “The recompense for any injury is an injury equal thereto (in degree): but if a person forgives and makes reconciliation, his reward is due from Allah: for (Allah) loves not those who do wrong.”
Another well-known verse says: “… repel (evil) with that which is better” (Qur’an 41:34). Surah 49:12 tells us to “avoid suspicion”. Surah 25:63 says: “And the servants of (Allah) Most Gracious walk the earth with humility and are those who, when the ignorant address them, say ‘Salaam’.”
Lastly Qur’an 45:14 refers specifically to forgiveness of those who have not understood or believed in Islam: “Tell those who believe to forgive those who do not look forward to the Days of Allah: It is for Him to recompense (for good or ill) each people according to what they have earned.”
All these verses of the Qur’an point in the direction of the moral superiority of openness, forbearance, forgiveness, magnanimity and good will over retaliation, whether for actual offences or for potential or imagined offences.
In conclusion, the ahadith specifically excluding the People of the Book from the salutations of Salaam have been understood by a group of scholars. They therefore ruled that it is unlawful to initiate salutations of salaam with non-Muslims such as Jews, Christians, Pagans, and Zoroastrians and others.
Another group considers the related verses of the Qur’an, several ahadith and the context surrounding the specific Hadith on prohibition, and viewed it to be permissible to initiate greetings of Salaam with a non-Muslim. This group understands the hadith on prohibition to be specific to a particular instance and context. In accordance with the view of this group of scholars, therefore, it is only the presence of similar hostile conditions that warrant the prohibition of initiating salaams with non Muslims.
It is worth mentioning that some Companions saw the salutations of Salaam to be a right of companionship. This implies that the context may also be important.
However, virtually all scholars seem to have no problem with responding to Salaam from non-Muslims in consideration of the instruction of Allah in Qur’an 4:86. They only differ on the format of the reply.
Greeting in whatever form is considered by Scholars of Principles of Jurisprudence (Usool al-Fiqh) to be among social transactions (Mu’amalat) regarding which the basic principle of Jurisprudence governing it is permissibility, except otherwise prohibited by Islamic Law (Sharia).