1256 – ʿAlī (may Allah be pleased with him) reported that the Messenger of Allah (peace and blessings be upon him) said: “It is sufficient for a group, when they pass by, that one of them give the greeting, and it is sufficient for the group that is greeted that one of them respond.” Related by Aḥmad and al-Bayhaqī. (1)

• Hadith grading:
  The hadith is ḥasan when all of its chains are taken together. It was also recorded by Abū Dāwūd, Aḥmad, al-Bayhaqī, Abū Yaʿlā, and al-Ḍiyāʾ in al-Mukhtārah. Al-Nīsābūrī said, “This is a sound (ḥasan) hadith,” and al-Ḥāfiẓ likewise graded it sound in Nataʾij al-Afkār.

• Points derived from the hadith:

1. As mentioned earlier, initiating the salām is a communal Sunnah (sunnah kifāyah); if one Muslim offers it the duty is lifted from the rest, though it is better if all of them greet.
2. Replying is a communal obligation (farḍ kifāyah); if one of them responds it suffices for the others, yet it is preferable that everyone reply.
3. The present hadith clarifies the minimum that discharges the duty.
4. Sharḥ al-Iqnāʿ states: Initiating the salām by a group is a communal Sunnah, and the preferred course is that all of them greet, in light of the hadith “Spread the salām” (Muslim 54). Replying is an individual obligation upon a lone person and a communal obligation upon a group; the obligation falls away if one of them replies.
5. The scholars have differed over the meaning of the word salām; some have said that it is one of the Names of Allah;