Musnad Abu Ya'la al-Mawsili 117:100

Shayban narrated to us, Hammad narrated to us, Thabit narrated from Anas that the Messenger of Allah (may Allah bless him and grant him peace) was visited by Gabriel while he was playing with the boys. He took him, laid him down, and split his chest. He extracted a blood clot from it and said, "This is the portion of Satan in you." Then he washed it in a basin of gold with Zamzam water, then he joined it together and returned it to its place. The boys came running to his mother—meaning his wet nurse—and said, "Muhammad has been killed." They went to meet him, and he was pale in color. Anas said, "I used to see the mark of that stitching on his chest."