In the south of Arabia, there is a place called Najran. There lived the Christian tribe of Najran who staunchly believed that Prophet Isa (a) i.e. Jesus was the son of God. The Prophet invited them to accept Islam. In response to that, a delegation of their priests and elders came to Madina. They wanted to discuss religion with the Holy Prophet Prophet Muhammad (S).
Their argument was that Jesus was born without a father, so he was the son of God. The Holy Prophet explained to them that just as Allah created Prophet Adam without a father or even a mother, in the same way He created Jesus without a father. Hence Jesus was a servant of Allah as was Prophet Adam. The Christians did not agree with this simple truth. They stuck to their belief that Jesus was the son of God. The Prophet asked them to wait. Then came the following Revelation (message from Allah):
“O Messenger! If they dispute with you in this matter after the knowledge has come to you, then, say, 'Come, let us call our sons and your sons, and our women and your women, and our souls and your souls. Then let us earnestly invoke and lay the malison (curse) of Allah on those who lie”. (Quran: Sura Ale lmran - verse 60)
It was then agreed that the Christians seek MUBAHALA with the Prophet. The meaning of MUBAHALA is that both of them invoke from Allah that he, who speaks the truth may survive and he, who is untrue may perish.
On the day of Mubahala, the Prophet of Islam took with him his grandsons - Imam Hasan (a) and Imam Husain (a), his daughter Fatima Zehra (a) and his cousin and son-in-law Imam Ali (a). But on seeing the radiant faces of these sinless members of the household of the Prophet, the Christians got scared. They decided not to seek Mubahala any more but accepted their defeat. They agreed to pay tribute and returned home.
The Prophet, before going for Mubahala, was commanded by Allah to take with him his sons, his women and his souls. The Holy Prophet obeyed this command as under:
In place of his sons, he took with him Imam Hasan (a) and Imam Husain (a). In place of women, he took Fatima Zahra (a). In place of his souls, he took Imam Ali (a).
This is how he showed to the world who the true and real members of his Ahlul Bait (People of the House of Prophet) were. To love them has been obligatory (wajib) command of Allah on every Muslim. The Holy Quran says:
“Say, I do not ask for return of this (messengership) from you except that you love (my) relatives.” (Sura As-shura , 26:23)
The Prophet and his Ahlul Bait sacrificed all the worldly comforts and even their lives in order to convey the true religion of Islam to us. In return of their sacrifices, we are commanded by God to love them. The aim is that through their love, we follow their footsteps. We follow the true teachings of Islam taught by them, so that we live a good and decent life in this world and earn the pleasure of God in the life hereafter.