Sunan Ibn Majah, Chapter: The Chapters on Rulings

the Quraish went to a sorceress and they said to her: "Tell us whose footprints most resemble those of the owner of Al-Maqam (the station of Ibrahim)." She said: "If you spread a piece of cloth over this soft earth and walk over it, I will tell you." So they spread out a piece of cloth and the people walked over it. She saw the footprints of the Messenger of Allah (saw) and said: "This one most closely resembles him among you." After that twenty years passed, of as long as Allah willed, then Allah sent Muhammad (saw) (i.e., missioned him as the Prophet).