Musnad Ahmad 32:1625

'Affan narrated to us, Khalaf bin Khalifah narrated to us. 'Abdullah said: My father said: "I saw Khalaf bin Khalifah, and a person said to him: 'O Abu Ahmad, did Muharib bin Dithar narrate to you?'" My father said: "I did not understand his speech; he had become old, so I left him." Hafs narrated to us, from Anas bin Malik, who said: The Messenger of Allah (ﷺ) used to command marriage and forbid celibacy strictly. He would say: "Marry the loving and the fertile, for I will boast of your great numbers before the prophets on the Day of Resurrection."