Musnad Ahmad 529:11

Haywah and Yazid ibn Abd Rabbih narrated to us, they said: Baqiyyah narrated to us, Buhayr ibn Sa'd narrated to me, from Khalid ibn Ma'dan, from Ibn 'Amr al-Sulami, from 'Utbah ibn 'Abd al-Sulami, that he narrated to them: That a man asked the Messenger of Allah, peace and blessings of Allah be upon him, and said: "How was the beginning of your affair, O Messenger of Allah?" He said: "My foster mother was from Banu Sa'd ibn Bakr. I and a son of hers went out with our sheep, and we did not take any provisions with us. I said: 'O my brother, go and bring us some provisions from our mother.' My brother went, and I remained with the sheep. Then two white birds approached, as if they were eagles. One of them said to his companion: 'Is it him?' He said: 'Yes.' They came toward me, rushed at me, took me, and laid me down on my back. They split my abdomen, then extracted my heart and split it. They took out two black clots from it. One of them said to his companion—Yazid said in his narration: 'Bring me snow water'—and they washed my interior with it. Then he said: 'Bring me hail water,' and they washed my heart with it. Then he said: 'Bring me the tranquility (al-sakinah),' and he scattered it into my heart. Then one of them said to his companion: 'Sew it up,' so he sewed it up and sealed it with the Seal of Prophethood." Haywah said in his narration: "Sew it up, so he sewed it up and sealed it with the Seal of Prophethood." Then one of them said to his companion: "Place him in a scale and place a thousand of his nation in a scale." I was looking at the thousand above me, fearing that some of them might fall upon me. He said: "If his nation were weighed against him, he would outweigh them." Then they departed and left me. I was terrified with a severe terror. Then I went to my mother and informed her of what I had encountered. She feared for me that I might have been possessed. She said: "I seek refuge for you with Allah." She saddled a camel of hers and placed me—Yazid said: "She carried me"—on the saddle, and she rode behind me until we reached my mother. She said: "Have I fulfilled my trust and my obligation?" She told her what I had encountered, but that did not frighten her. She said: "I saw a light emerge from me, by which the palaces of Ash-Sham were illuminated."