Musnad Ahmad 25:1391

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from Ayyub and Kathir ibn Kathir ibn al-Muttalib ibn Abi Wada'ah—one of them adding to the other—from Sa'id ibn Jubayr, Ibn 'Abbas said: "The first time women took to wearing a waist-belt (mintaq) was from the mother of Isma'il; she took a waist-belt to conceal her tracks from Sarah," and he mentioned the hadith. Ibn 'Abbas said: "May Allah have mercy on the mother of Isma'il. Had she left Zamzam—or he said: Had she not scooped from the water—Zamzam would have been a flowing spring." Ibn 'Abbas said: The Prophet, peace and blessings of Allah be upon him, said: "The mother of Isma'il found that, and she loved company, so they settled and sent for their families, and they settled with them." And he said in his hadith: "She descended from al-Safa, until when she reached the valley, she lifted the edge of her garment, then she ran the running of a person exerting effort, until she crossed the valley. Then she came to al-Marwah and stood upon it and looked: did she see anyone? But she did not see anyone. She did that seven times." Ibn 'Abbas said: The Prophet, peace and blessings of Allah be upon him, said: "That is why people perform the sa'i (running/walking) between them."