The best of you is the one who feeds others

Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said to Sayyiduna Suhayb (may Allah be pleased with him): How fine a man you would be, were it not for three traits (needing correction) in you. He asked: What are they? He said: You have taken a kunyah even though you have no children; you ascribe yourself to the Arabs although you are a Roman; and you are very extravagant in food. He replied: O Commander of the Believers! As for your first point, that I took a kunyah without having children, the Messenger of Allah (peace and blessings be upon him) himself gave me the kunyah "Abu Yahya". As for your saying that I ascribe myself to the Arabs, the truth is that I am a member of the tribe of al-Namir bin Qasit; I was taken captive from Mosul in my childhood, when I already knew my family and lineage. And as for your saying that I am extravagant in food, I heard the Messenger of Allah (peace and blessings be upon him) say: "The best of you is the one who feeds others."
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna Abu Bakrah (may Allah be pleased with him) that he said: When the Messenger of Allah (peace and blessings be upon him) besieged Ta'if, I let myself down (from the fortress) by means of a pulley (bakrah). He (peace and blessings be upon him) asked: How did you do this? I said: I came down by means of a "bakrah". So he (peace and blessings be upon him) said: "You are Abu Bakrah."
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

Al-Miqdam bin Shurayh narrates from his father, and he from his grandfather (may Allah be pleased with him), that he said: The Messenger of Allah (peace and blessings be upon him) asked me: "Which of your children is the eldest?" I said: Shurayh. He (peace and blessings be upon him) said: "Then you are Abu Shurayh."
Qays is alone in narrating this from al-Miqdam, and after it I mention a hadith that Mujalid bin Sa'id alone narrates; and these two (Qays and Mujalid) do not meet the conditions of this book (al-Mustadrak).

Masruq narrates that he said: I came to Sayyiduna Umar (may Allah be pleased with him), and he asked: What is your name? I said: Masruq. He asked: Whose son are you? I said: Ibn al-Ajda'. He said: You are "Masruq bin Abd al-Rahman". The Messenger of Allah (peace and blessings be upon him) told us that "al-Ajda'" is the name of a devil. So his name was recorded in the official register (diwan) as Masruq bin Abd al-Rahman.

It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that a man called out to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said in reply: "Ya labbayk" (Here I am).
This hadith is sahih (authentic), but the two Shaykhs (Bukhari and Muslim) did not record it.