Sahih Muslim, Chapter: Faith (Kitab Al Iman)

that Gabriel came to the Messenger of Allah (may peace be upo him) while he was playing with his playmates. He took hold of him and lay him prostrate on the ground and tore open his breast and took out the heart from it and then extracted a blood-clot out of it and said: That was the part of Satan in thee. And then he washed it with the water of Zamzam in a golden basin and then it was joined together and restored to it place. The boys came running to his mother, i. e. his nurse, and said: Verily Muhammad has been murdered. They all rushed toward him (and found him all right) His color was changed, Anas said. I myself saw the marks of needle on his breast.