The moment he sat, Hazrat Abbaas (radhiyallahu ‘anhu) addressed the Ansaar saying, “Muhammed (sallallahu ‘alaihi wasallam) is greatly honoured and revered in his community. (Although people opposed the deen of Rasulullah (sallallahu ‘alaihi wasallam), they showed him such exceptional honour and reverence which was not accorded to anyone else.) We are his staunch supporters and loyal protectors. He wishes to come over to Madinah Munawwarah and reside among you. If you are capable of providing your loyal support and absolute protection to him and you sincerely believe that you will remain committed to this pledge until you die, then well and good. Otherwise, you should give me an honest answer now.”
The Ansaar replied, “We have heard what you said and we understand your concerns.” Then then addressed Rasulullah (sallallahu ‘alaihi wasallam) and said, “O Prophet of Allah (sallallahu ‘alaihi wasallam)! Whatever you want from us, we are eagerly ready to comply. Whatever you and Allah Ta‘ala want from us, we are prepared to accept it and you may even take a pledge from us.”
Rasulullah (sallallahu ‘alaihi wasallam) replied, “I am inviting you towards Allah.” He then presented them with Islam and recited a few verses of the Qur’aan Majeed before them. He then proclaimed, “In regard to Allah Ta‘ala, I ask you to worship Him alone and to refrain from ascribing any partner unto Him. In regard to my companions (and myself), I request you to grant us refuge and safety, to protect and defend us just as you would protect and defend your own wives and children, and that you will obey me in times of happiness and sadness, in comfort and adversity, in prosperity and in poverty. In every condition, you must obey me and adhere to what I command you to do.”
The Ansaar asked, “If we do this, then what will we get in return?” Rasulullah (sallallahu ‘alaihi wasallam) replied, “You will receive Jannah! (i.e. the eternal bounties of the Hereafter)”
The Ansaar replied, “We accept all your conditions! Come, and extend your blessed hand so that we may pledge our allegiance to you!”
(Extracted from Seeratul Mustafa 1/341-342)