“Mubahalah or prayer-duel, a synonym of mula‘anah, literally means “mutual imprecation, curse” (e.g., “may God’s curse over the one of us who is wrong, who lies”), implies swearing a conditional curse (e.g., “may God’s punishment hit me, may I be cursed if…”) and a purifying oath. (EI, New Ed. (1993), Vol. 7, pp. 276 f.) Thus, a mubahalah is invoked by two parties to call upon God’s curse or judgement to determine who is truthful, as mentioned in the following verse of the Holy Quran:

فَمَنۡ حَآجَّكَ فِيۡهِ مِنۡۢ بَعۡدِ مَا جَآءَكَ مِنَ الۡعِلۡمِ فَقُلۡ تَعَالَوۡا نَدۡعُ اَبۡنَآءَنَا

وَاَبۡنَآءَكُمۡ وَنِسَآءَنَا وَنِسَآءَكُمۡ وَاَنۡفُسَنَا وَاَنۡفُسَكُمۡ ۟ ثُمَّ نَبۡتَهِلۡ فَنَجۡعَلۡ لَّعۡنَتَ اللّٰهِ عَلَي الۡكٰذِبِيۡنَ “Now whoso disputes with thee

concerning him, after what has come to thee of knowledge, say [to him], ‘Come, let us call our sons and your sons, and our women and your women, and our people and your people; then let us pray fervently and invoke the curse of Allah on those who lie.’” (Surah Aal-e-Imran, Ch.3: V.62)

The term ‘mubahalah’, as mentioned in this article, refers to a historical event that took place during a theological dispute between the Holy Prophet Muhammadsa and a delegation of Christians from the town of Najran. To resolve the dispute, the Prophetsa proposed a mubahalah. The Najranis, who had initially agreed to participate in the mubahalah, had second thoughts after realising the potential consequences. Hence, the mubahalah was avoided altogether, and they were granted a treaty of protection with specific rights and duties as non-Muslims. (EI, New Ed. (1993), Vol. 7, pp. 276 f.)” https://www.alhakam.org/islam-today-did-prophet-muhammads-mubahalah-challenge-fail/#:~:text=Mubahalah%C2%A0or%20prayer%2Dduel%2C%20a%20synonym%20of%C2%A0mula%E2%80%98anah%2C%20literally,Muslims.%20(EI%2C%20New%20Ed.%20(1993)%2C%20Vol.%207%2C%20pp.%20276%20f.)