Musnad Ahmad 1245:1

Rawh and Abu Nu'aym narrated to us, they said: Hisham bin Abi 'Abdullah narrated to us, from Budayl bin Maysarah, from Safiyyah bint Shaybah, from the mother of a child of Shaybah, that she saw the Prophet, may God bless him and grant him peace, while he was performing Sa'i between al-Safa and al-Marwah, saying: "The valley (al-Abtah) is not crossed except by running."