In case...
In case, therefore, you feel that you will desert him when you are required to spend your wealth for his sake or when your elders are killed you should abandon the idea of taking the oath of allegiance just now, because by Allah such an action is the cause of disgrace in this world as well as in the Hereafter.
However, if you feel that even after spending wealth and in spite of your nobles and elders being killed you will remain faithful to him, you must not forsake him, because I swear by Allah that in this lies the happiness of both the worlds. Thereupon all of them said with one voice: "We are ready to take the oath of allegiance notwithstanding the fact that we have to sacrifice our wealth and our elders are killed".
Then they asked the Holy Prophet: "What shall we gain if we remain faithful?" He replied: "The Paradise". They said: "Then stretch forth your hand so that we may take the oath of allegiance to you". According to Ibn Ishaq the Holy Prophet commenced his discourse by reciting the Holy Qur'an, inviting them to Allah and encouraging them to embrace Islam. He then said: "I accept your allegiance on the condition that you will support me in the same manner in which you support your women and children".
Bara bin Marur held the hand of the Holy Prophet and said: "I swear by Allah who has sent you as the true Prophet that we will certainly defend you in the same manner in which we defend our women and our honor. O Prophet of Allah! Do accept our oath of allegiance. By Allah we are well-versed in fighting and are ready to fight. In fact we have inherited warfare as our way of life from generation to generation".
At this stage Abul Haitham bin Tayhan who was one of the elders of the Ansar and the martyrs of Siffin interrupted Bara bin Marur and said: "A Prophet of Allah! There are relations between the Jews and us and we are going to sever them now.
Let it not be that we should leave our confederates and later when Allah makes you successful you should return to your people and leave us helpless", The Holy Prophet smiled and said: "This will never happen and the contrary your blood is my blood and my honor is your honor. I belong to you and you belong to me. I will fight against anyone who fights against you, and will be at peace with him who is at peace with you".