It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that when the Messenger of Allah (peace and blessings be upon him) came to Madinah, Sayyiduna Abdullah bin Salam (may Allah be pleased with him) was (busy) up a date palm. Sayyiduna Abdullah bin Salam (may Allah be pleased with him) came to the Messenger of Allah (peace and blessings be upon him) and said: "I want to ask you about some things that no one knows except a prophet; if you answer me about them, I will believe in you." (The narrator then related the full hadith.)
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13961
Sayyiduna Anas bin Malik (may Allah be pleased with him) relates that Sayyiduna Abdullah bin Salam (may Allah be pleased with him) said: O Messenger of Allah, I have become a Muslim, and I would like to ask you about some things. He (peace and blessings be upon him) said: "Ask whatever you wish." I said: O Messenger of Allah, tell me why a child resembles his mother when the seed comes from the man. He (peace and blessings be upon him) said: "The man's fluid is white and thick and the woman's fluid is red and thin; whichever of the two prevails, the child resembles it." I said: O Messenger of Allah, what will the people of Paradise eat when they enter it? He (peace and blessings be upon him) said: "The caudate lobe of a fish's liver." I said: O Messenger of Allah, tell me about the signs of the Hour. He (peace and blessings be upon him) said: "A fire that will come out from the east and drive people to their place of gathering." (On hearing this) Sayyiduna Abdullah bin Salam (may Allah be pleased with him) said: I bear witness that you are the Prophet of Allah.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13962