The Holy Prophet (S) had sent letters to the heads of different countries inviting them to Islam. One such letter was addressed to the Christians of Najran.

When they received the letter they decided to meet the Holy Prophet (S) in person. The group arrived in Madina and entered the mosque wearing silk clothes, golden rings and crosses around their necks. On seeing them dressed in this fashion, the Holy Prophet (S) was disturbed and he ignored them. They realised that something was wrong but were unsure as to what to do.

On the advice of Imam Ali (A) they changed their style of dress to simple clothes and removed their ornaments. They then returned to the Holy Prophet (S) who received them with a warm welcome.

Before they entered into a discussion, they requested for permission to say their prayers and this was granted.

Then the discussion began, the people of Najran would not listen to the Holy Prophet (S) and said that they believed in Prophet Isa (A) as the son of God because he had no father.

At this time, angel Jibraeel (A) brought the following verse of the Holy Qur'an from Allah (Sura Aale Imran, verse 59):

"Surely the example of Isa to Allah is like that of Adam; He created him from dust, and then said to him, "Be!" and he was." (3 : 59)

This meant that if Prophet Isa (A) could be called the son of God because of the fact he was born without a father, then Prophet Aadam (A) deserved this title more, because he was born without a father or mother.

The Christians could not reply to this argument but they continued to argue out of obstinacy. Then the following verse of the Holy Qur'an was revealed (Sura Aale Imran, verse 61):

"And whoever argues with you in this matter after what has come to you of knowledge, then say, "Come, let us call our sons and your sons and our women and your women and ourselves and yourselves, then let us humbly pray (to our Lord) and invoke the curse of Allah upon the liars." (3:61)

The Holy Prophet (S) produced this verse before the Christians and declared the challenge of "Mubahila", which means to curse one another. The Christians accepted the challenge.

The next day on the 24th of Zilhaj 9 A.H., the Holy Prophet (S) came out for Mubahila. He held Imam Husain (A) in his arms and he held Imam Hasan (A) by his hand. Hazrat Fatima (A) came behind him, while behind her came Imam Ali (A). The Holy Prophet (S) said to them, "when I pray you should say Ameen."

In obedience to the verse of Mubahila sent by Allah, the Holy Prophet (S) had brought Imam Hasan (A) and Imam Husain (A) as his "sons", Hazrat Fatima (A) as his "women" and Imam Ali (A) as his "self".

The Christians, on seeing the beautiful and shining faces in front of them began to tremble and shake.

They backed away from Mubahila, and admitted defeat.