Disavowal of Disbelievers by Imam Ali (A.S.)

On 1st of the Islamic month of Zil-Hajjah in 9 AH, shortly after Prophet Mohammad (SAWA) had dispatched to Mecca his companion Abu Bakr with the opening ayahs of Surah Towba to clarify the rules of the Hajj pilgrimage and to declare disavowal of disbelievers, Archangel Gabriel descended with the divine commandment, saying that either the Prophet should personally discharge this mission at the holy Ka'ba or depute the one who is nearest to him.
The Prophet promptly sent his dear ward, cousin and son-in-law, Imam Ali (AS), to overtake Abu Bakr and assume personal charge of the mission. Abu Bakr returned to Medina, while Imam Ali (AS) proceeded to Mecca, where without fear of the infidels, he clarified the rules of the Hajj through practical demonstration, while performing the pilgrimage.
For three days the Imam continuously recited the opening ayahs of Surah Towba concerning “bara'at min al-mushrikeen” (disavowal of disbelievers), and made it clear that neither the polytheists are allowed anymore to enter the sacred precincts of the Ka'ba, nor should anyone follow the pagan practice of circumambulating the holy edifice naked, without clothes. Thus till this day, all Muslims are indebted to the Holy Prophet (SAWA) and Imam Ali (AS) for reviving the pure Abrahamic rituals of the Hajj pilgrimage by God's command.