Tafsir of An-Nisa' 4:86

"The better one" means that if someone says, "Peace be upon you" (al-salāmu ʿalaykum), you should respond with, "And upon you be peace and the mercy of Allah" (wa-ʿalaykum al-salāmu wa-raḥmatu-llāh). If they say, "And the mercy of Allah," you should add, "and His blessings" (wa-barakātuhu).

It is narrated that a man said to the Messenger of Allah (ﷺ), "Peace be upon you," and he replied, "And upon you be peace and the mercy of Allah." Another said, "Peace be upon you and the mercy of Allah," and he replied, "And upon you be peace, the mercy of Allah, and His blessings." A third man said, "Peace be upon you, the mercy of Allah, and His blessings," and he replied, "And upon you." The man said, "You have diminished my greeting; where is what Allah said?" and he recited the verse. The Prophet (ﷺ) replied, "You left me no room for increase, so I returned to you the like of what you gave." (Weak)

"Or return it" means: answer it with the like thereof. Returning the greeting is called radd (repetition) because the responder repeats the words of the greeter. Responding to the greeting is obligatory; the choice lies only between adding to it or merely returning it.

• Al-Nakhaʿī: The greeting is a Sunnah, but the response is a religious obligation (farīḍah).
• Ibn ʿAbbās: The response is obligatory.
• Abū Yūsuf: If someone asks you to convey a greeting to another, it is obligatory to do so.

Whoever passes by a group of Muslims and greets them, and they do not return the greeting, the Holy Spirit (Rūḥ al-Quds) is withdrawn from them, and the angels return the greeting instead.

Exceptions: One should not return a greeting during a sermon (khuṭbah), while reciting the Quran aloud, while narrating Hadith, during scholarly discourse, or during the Adhān and Iqāmah.

Abū Yūsuf adds: Do not greet those playing dice or chess, singers, those relieving themselves, pigeon-fanciers, or those naked without excuse in a bathhouse or elsewhere. Al-Ṭaḥāwī mentioned that it is recommended to be in a state of ritual purity (ṭahārah) when returning a greeting, as the Prophet (ﷺ) performed tayammum to return a greeting.

Etiquette:

• A man should greet his wife upon entering, but should not greet a strange woman.
• The walker greets the sitter, the rider greets the walker, the rider of a horse greets the rider of a donkey, the younger greets the elder, and the smaller group greets the larger group.
• If two people meet, they should both hasten to greet.
• Abū Ḥanīfah: Do not raise your voice excessively when returning the greeting.

Regarding People of the Book: The Prophet (ﷺ) said: "If the People of the Book greet you, say: 'And upon you' (wa-ʿalaykum)." (Authentic). This means: "And upon you be what you have said," because they used to say, "Death be upon you" (al-sāmu ʿalaykum).

It is narrated: "Do not initiate the greeting to a Jew, but if he greets you, say: 'And upon you'." (Authentic).

• Al-Ḥasan: It is permissible to say to a disbeliever, "And upon you be peace," but do not add "and the mercy of Allah," for that is a prayer for forgiveness.
• Al-Shaʿbī: He once said to a Christian who greeted him, "And upon you be peace and the mercy of Allah." When asked about this, he replied, "Does he not live within the mercy of Allah?"
• Some scholars permit initiating the greeting to the Dhimmīs if a situation necessitates it.
• Abū Ḥanīfah: Do not initiate the greeting to them in writing or otherwise.
• Abū Yūsuf: Do not greet them or shake their hands. If you enter a gathering, say: "Peace be upon those who follow guidance."
• There is no harm in praying for their worldly well-being.

"Indeed, Allah is ever, over all things, an Accountant." Meaning: He will hold you accountable for everything, including the greeting and other matters.