A slave-mother (umm walad) of Shaybah (may Allah be pleased with her) says: I saw the Messenger of Allah (peace and blessings be upon him) through a small window; he was performing the sa'i in the bed of the watercourse between al-Safa and al-Marwah, and he was saying: "The valley, or al-Abtah, is not to be crossed except at a run."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9368