Then let us call on God to witness against each other and...
Then let us call on God to witness against each other and let us make the curse of God fall on those who lie (III 61). The Prophet, may God bless him and his family, recited it to the Christians and challenged them to a contest of prayer to God (mubahala).
He said: "God, the Mighty and High, has informed me that dread torment will come down on him who has spoken falsely after the contest of prayer (mubahala).By this the truth will be distinguished from the false." The Bishop held a meeting of consultation with 'Abd al-Masih and the deputy. Their unanimous view was to wait until the early morning of the next day. When they both returned to their men, the bishop told them: "Watch Muhammad tomorrow morning.
If he comes out with his children and his family, then be warned against the contest of prayer (mubahala) with him. However, if he comes out with his , then make the contest of prayer with him, for he believes in something other (than the true religion)." On the next morning, the Prophet, may God bless him and his family, came and took 'Ali b. Abi Talib by the hand, while al-Hasan and al-Husayn, peace be on them, were walking in front of him and Fatima, peace be on her, walked behind him.
The Christians came out, at their head their bishop. When the bishop saw that the Prophet, may God bless him and his family, was advancing with those who were with him, he asked about them. He was told: "That is his cousin 'Ali b. Abi Talib, who is his son-in-law and the father of his two grandsons and the most lovable of creatures to him. Those children are the sons of his daughter by 'Ali, peace be on him. They are the most lovable of creatures to him.
That girl is his daughter, Fatima, peace be on her, the dearest of people to him and the closest to his heart." The bishop looked at the deputy, the chief and 'Abd al-Masih and said: "Have you seen that he has come with the special members of his children and his family so that he may make the contest of prayer with them, trusting in his truthfulness. By God, he would not have come with them while he was afraid that the proof would be against him.
Therefore be warned against the contest of prayer with him. By God, if it was not for the position of Caesar (i.e. the Byzantine emperor), I would submit to him. But (now) make peace with him on what can be agreed between you and him. Return to your land and think about it yourselves." "Our view conforms with your view," they replied.