Mishkat al-Masabih #2473

Safiya daughter of Shaiba said that the daughter of Abu Tujrat told her she had entered the house of the family of Abu Husain along with some women of Quraish and they had watched God’s messenger while he was running between as-Safa and al-Marwa. She saw his lower garment moving round as he ran because of the vigour with which he did it, and she heard him saying, “Run, for God has prescribed running for you." It is transmitted in Sharh as-sunna, and Ahmad transmitted it with some difference.