A man returning another's greeting: how should he reply?

Zahrah bin Humaydah said: I was riding behind Sayyiduna Abu Bakr (may Allah be pleased with him) when we passed by some people. We greeted them with salam, and they returned our salam with much more than we had said. At this Sayyiduna Abu Bakr (may Allah be pleased with him) said: Today the people are surpassing us in reward.

Zayd bin Wahb said that Sayyiduna Umar (may Allah be pleased with him) said: I was riding behind Sayyiduna Abu Bakr (may Allah be pleased with him). Then he mentioned the aforementioned hadith, and said: Today the people have outstripped us in reward.

Abu al-Bakhtari said: A man came to Sayyiduna Ali (may Allah be pleased with him) and said: O Commander of the Faithful! As-salamu alayka wa rahmatullahi wa barakatuh (peace be upon you, and the mercy of Allah and His blessings). He said: Wa alaykum (and upon you). The man thought he had not heard, so he said again: O Commander of the Faithful! As-salamu alayka wa rahmatullahi wa barakatuh. He said: Wa alaykum. The man said: Why do you not answer me as I have said to you? He said: Have I not done so?

Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: A man entered the mosque while the Messenger of Allah (peace and blessings be upon him) was sitting in a corner of the mosque. The man prayed, then gave the salam to him (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Wa alayka as-salam, and peace be upon you as well."

Malik bin Aws bin al-Hadathan said that Sayyiduna Abu Dharr (may Allah be pleased with him) returned from Syria and entered the mosque, while Sayyiduna Uthman (may Allah be pleased with him) was also in the mosque. He said: As-salamu alaykum (peace be upon you). He replied: Wa alaykum as-salam (and upon you be peace). How are you, O Abu Dharr? He said: I am well. How are you, O Uthman? He replied: I too am well.

Maymun said that a man greeted Sayyiduna Salman al-Farisi (may Allah be pleased with him) and said: As-salamu alayka wa rahmatullahi wa barakatuh (peace be upon you, and the mercy of Allah and His blessings). Sayyiduna Salman (may Allah be pleased with him) said: Enough, enough. Then he answered him just as the man had greeted, and then added some further words. At this the man asked him: O Abu Abdullah! Do you know me? He said: My soul knows your soul.

Nafi' said that Sayyiduna Ibn Umar (may Allah be pleased with them both) would return the salam just as it was said to him, for example: As-salamu alaykum (peace be upon you).

Mu'awiyah bin Qurrah said: My father advised me: When you are greeted with salam, do not say in reply 'Wa alayka', but say 'Wa alaykum', for there are angels with that person.

Abd al-Rahman al-Rahhal said that when al-Rabi' bin Khuthaym returned the salam he would say 'Wa alaykum', and he would intend the reply for the one who gave the salam.

Abu Ishaq said that when Shurayh returned the salam he would say: Wa alaykum, that is, and upon you.

Al-A'mash said that when Zayd bin Wahb was greeted with salam he would reply: Wa alaykum as-salam wa rahmatullahi wa barakatuhu wa maghfiratuh (and upon you be peace, and the mercy of Allah, His blessings and His forgiveness).

Al-A'mash said that Ibrahim said: When a man returns the salam, he should use the plural form and say 'Wa alaykum', because there are angels with the person.

Isma'il and Ibn Awn both said that when Ibrahim returned the salam he would say: Wa alaykum wa rahmatullah (and upon you, and the mercy of Allah).

Ibn Awn said that when Imam Muhammad (Ibn Sirin) returned the salam he would say: Wa alaykum.