Sahih Muslim Book 7, Hadith Number 2927.

Chapter : Sa’i between al-Safi’ and at-Marwi is essential rite of Hajj and Hajj is not complete without it.

‘Urwa b. Zabair narrated on the authority of ‘Aisha (Allah be pleased with her) who informed him that the Ansar and the people of the tribe of Ghassan before embracing Islam pronounced Talbiya for Manat, and so they avoided circumambulating’ between al-Safa’ and al-Marwa, and it was a common practice with their forefather, that he who put on Ihram for Manat did not circumambulate between al-Safa’ and al-Marwa. And when they embraced Islam, they asked Allah’s Messenger (may peace be upon him) about it, and then Allah, the Exalted and Majestic, revealed this verse: “Verily al-Safa’ and al-Marwa are among the Signs of Allah”; so he who performs Hajj or Umra, for him there is no harm if he should circumambulate between them, and he who does good spontaneously-surely Allah is Bountiful in rewarding and Knowing.