Abdullah bin Salam came to the Messenger of Allah ﷺ when he arrived in Medina and said, "Messenger of Allah, I am going to ask you about three things which only a prophet would know."He replied, "Ask."Abdullah said, "What is the first sign of the Hour? What is the first food the people of Paradise will eat? And how does a child come to resemble his father or his mother?"The Messenger of Allah ﷺ said, "Jibreel has just informed me of these matters."Abdullah said, "He is the enemy of the Jews among the angels."The Messenger of Allah ﷺ said, "As for the first sign of the Hour, it is a fire that will come out from the east and drive the people toward the west. As for the first food the people of Paradise will eat, it is the lobe of the fish's liver. As for the resemblance of a child to his father or mother, when the man's fluid precedes the woman's, the child resembles him, and when the woman's fluid precedes the man's, the child resembles her."Abdullah said, "I bear witness that there is no god but Allah, and that you are the Messenger of Allah." Then he said, "Messenger of Allah, the Jews are a people given to slander. If they learn of my Islam before you ask them about me, they will slander me in your presence. So send for them and ask them about me."The Prophet ﷺ sent for them and asked, "What sort of man is Abdullah bin Salam among you?"They replied, "He is the best of us and the son of the best of us, the most learned of us and the son of the most learned of us, the most knowledgeable of us in religion and the son of the most knowledgeable of us."He asked, "What would you say if Abdullah were to embrace Islam?"They said, "May Allah protect him from that!"Then Abdullah came out and declared, "I bear witness that there is no god but Allah, and that Muhammad is the Messenger of Allah."They said, "He is the worst of us and the son of the worst of us, the most ignorant of us and the son of the most ignorant of us."Ibn Salam said, "This is exactly what I feared."
حدثنا ابن أبي عدي عن حميد
أن عبد الله بن سلام أتى رسول الله ﷺ مقدمه المدينة فقال يا رسول الله إني سائلك عن ثلاث خصال لا يعلمهن إلا نبي قال سل قال ما أول أشراط الساعة وما أول ما يأكل منه أهل الجنة ومن أين يشبه الولد أباه وأمه فقال رسول الله ﷺ أخبرني بهن جبريل عليه السلام آنفا قال ذلك عدو اليهود من الملائكة قال أما أول أشراط الساعة فنار تخرج من المشرق فتحشر الناس إلى المغرب وأما أول ما يأكل منه أهل الجنة زيادة كبد حوت وأما شبه الولد أباه وأمه فإذا سبق ماء الرجل ماء المرأة نزع إليه الولد وإذا سبق ماء المرأة ماء الرجل نزع إليها قال أشهد أن لا إله إلا الله وأنك رسول الله وقال يا رسول الله إن اليهود قوم بهت وإنهم إن يعلموا بإسلامي يبهتوني عندك فأرسل إليهم فاسألهم عني أي رجل ابن سلام فيكم قال فأرسل إليهم فقال أي رجل عبد الله بن سلام فيكم قالوا خيرنا وابن خيرنا وعالمنا وابن عالمنا وأفقهنا وابن أفقهنا قال أرأيتم إن أسلم تسلمون قالوا أعاذه الله من ذلك قال فخرج ابن سلام فقال أشهد أن لا إله إلا الله وأن محمدا رسول الله قالوا شرنا وابن شرنا وجاهلنا وابن جاهلنا فقال ابن سلام هذا الذي كنت أتخوف منه
Its isnad is sahih. It is found in Bukhari with similar wording, 7/272, no. 3938, Fath al-Bari, in Manaqib Ansar, chapter 51, and in Muslim with different wording, 1/252, no. 315, in Hayd, chapter on the description of a man's semen, at greater length than this.