‘Abdullah Ibn Salam heard about the arrival of the Prophet to Madinah, he came to him and asked him about some things saying:
“I will ask about three things that none except a messenger knows: what is the first sign of the Hour? What is the first meal that the dwellers of Paradise eat? Why is it that the child sometimes resembles his father and other times his mother?”
The Prophet said:
“Jibreel (Gabriel) informed about this earlier. Ibn Salam said:
“That is the Jews’ enemy from the angels.” The Prophet said:
“As for the first sign of the Hour, it is a fire that gathers the people from the East and the West.
As for the first meal that the dwellers of Paradise eat, it is a portion of the fish liver.
As for the child, if the water (i.e. sperm) of the man comes before that of the woman, the child resembles his father and if the mother’s water comes first then the child resembles her.”
Thereupon, Ibn Salam said:
“I bear witness that none has the right of being worshipped but Allah and that you are His messenger.”
Then Ibn Salam said:
“O Prophet of Allah, the Jews are people of falsehood. So ask them about me before they realize that I have become Muslim. The Jews came and the Prophet asked them:
“How do you grade ‘Abdullah Ibn Salaam within your community.”
They said: “Our best and the son of our best.”
Thereupon, the Prophet said:
“What if ‘Abdullah Ibn Salam becomes Muslim?”
They said: “May Allah protect him from that!”
The Prophet then repeated the same questions and the Jews repeated the same answers. At that time, ‘Abdullah Ibn Salam came out to them and said:
‘I bear witness that none has the right to be worshipped but Allah and that Muhammad is His messenger.’
Thereupon, they (the Jews) said:
“He is our worst and the son of our worst,” and demeaned him. Ibn Salam said:
‘This is what I feared, O Prophet of Allah.’” (Al-Bukhari)
Ahmad reported that Ibn Abbaas said:
“A group of Jews came one day to the Prophet and said:
‘O Abu Al-Qaasim, tell us some things that only true messengers of Allah know.’
The Prophet said:
“Ask me about whatever you wish, but promise me by the Name of Allah and by the covenant Prophet Ya’qoob, may Allah exalt his mention, took from his sons, that if I tell something that you know, then you will follow me and become Muslims.”
They said:
“That’s for you.”
Thereupon they said:
“Tell us about the following four things: tell us about the meal that Israel forbade himself before the revelation of the Torah and tell us about the water (sperm) of the woman and the water of the man how is the male child formed from that? And tell us this illiterate Prophet during his sleep and who is his guardian from the angels.”
The Prophet said:
“Do you accept by the covenant of Allah that you will follow me if I inform you?”
They gave him as much covenant and promise as he wished. Then the Prophet said:
“I ask you by the One Who revealed the Torah to Moses (peace be upon him) do you know that Israel (Ya’qoob, peace be upon him) fell badly sick and his sickness took a long time, then he made a vow to Allah that he would forbid on himself the food he liked most if Allah cures him, and the food he liked most was camel meat and the drink was camel milk.”
They said:
“Yes.”
He said:
“O Allah testify against them.”
Then he said:
“I ask you by Allah, the One Who has no partners Who revealed the Torah to Moses (peace be upon him) do you know that the man’s water is white and thick and that the woman’s water is yellow and thin. Any of the two waters gets above the other gets the resemblance of the child in his sex and characters by the will of Allah. If the water of the man gets over the woman it is a male by the Will of Allah and if the water of the woman gets above that of the man then it is a female by the Will of Allah.”
They said:
‘By Allah what you said is true.’
The Prophet said:
“O Allah testify against them.”
Then he said:
“I ask you by the One Who revealed Torah to Moses (peace be upon him) do you know that the eyes of this illiterate Prophet sleep but his heart does not.”
They said: ‘By Allah that is true.’
He said:
“O Allah, testify against them.”
They said: ‘You, now tell us about your guardian from the angels, we will stay with you or leave you according to that.’
He said:
“My guardian is Jibreel (Gabriel) and Allah never sent any Prophet but he was his guardian.”
The Jews said:
‘So, we will separate from you. Had your guardian been another angel not Jibreel, we would have followed you and believed in what you brought.’
The Prophet said:
“But what prevents you from believing in him?”
They said: ‘He is our enemy.’
Then Allah revealed the following verses (which means):
{Say, “Whoever is an enemy to Gabriel – it is [none but] he who has brought it [i.e. the Quran] down upon your heart, [O Muhammad], by permission of Allah,…} (Quran 2:97)
{And when a Messenger from Allah came to them confirming that which was with them, a party of those who had been given the Scripture threw away the Book of Allah behind their backs as if they did not know.} (Quran 2:101)
{So they returned having [earned] wrath upon wrath} (Quran 2:90)
From the book “Tafsir Ibn Kathir”, part 4, pages 9-10