Hazrat Ali Bin Abi Talib(RA)

      After Hazrat Usman(RA),Hazrat Ali Bin Abi Talib became the caliph.He was the son of Prophet Muhammad(SAWW)'s Uncle.His family was a well known family in Kabah with religious respect.Our Prophet Hazrat Muhammad(SAWW) had many uncles but the relationship with Hazrat Ali's Father Abu Talib was not found in any other relation.At the time when all the Makah residents were against Prophet Muhammad(SAWW) Hazrat Abu Talib supported and backed up Hazrat Muhammad(SAWW) and Hazrat Fatima(RA) also supported Prophet(SAWW) at really hard times.That was the only reason because of which Prophet(SAWW) loved the children of Hazrat Abu Talib.
     Financial Background of Abu Talib was not fair enough thats why Prophet(SAWW) Adopted Hazrat Ali(RA) so that the burden on Hazrat Abu Talib's Arms will decrease to some extend.That was the only reason that when Prophet(SAWW) declared and announced the Religion "ISLAM" the first person to say,"Labaik" was Hazrat Ali(RA).Due to studying under Hazrat Muhammad(SAWW) Hazrat Ali was so distant from the barbarism in the city of Makah at that time.
     After accepting Islam Hazrat Ali(RA) attended so many Tabligh's and Jalsa's with Prophet(SAWW).When Prophet(SAWW) Gathered all his family members for the announcement that(In Urdu),"Aey Bani Mutalib main tumhare samne Dunya aur Akhrat ka behtreen namona paish karta hun,Tum main se kaun mera sath deta hai,Kaun mera mauvin aur madadgar banta hai?"At that time there was only one voice and that voice was of Hazrat Ali(RA) he said(In Urdu),"Main umar main chota hun aur meri tangen bhe kamzoor hain par main aapka mauvin aur madadgar aur quat-e-bazo banunga"
   
Reference:
Page No:244 and 245
Tareekh-e-Islam By Shah Moin Uddin Ahmed Nadvi