What is the ruling on drinking poison in debates between a Muslim and a Christian to test which of the two religions is the truth, based on the hadiths: "In the name of Allah, with Whose Name nothing whatsoever on earth or heaven can inflict any harm; He is the All-Hearing, the All-Knowing" and "If they drink anything poisonous, it will not harm them"?

It is forbidden to consume anything that harms the body, such as poison, because Allah Almighty says: (And do not kill yourselves) and (And do not throw yourselves with your own hands into destruction). As for what has been reported about Khalid ibn al-Walid drinking poison and surviving, it is among the miracles that cannot be analogized or taken as a basis.

There are legitimate invocations (adhkar) that protect from harm, including: 1. The Hadith of Uthman ibn Affan, may Allah be pleased with him, that the Prophet, peace and blessings be upon him, said: (Whoever says: In the Name of Allah, with Whose Name nothing on earth or in the heavens can cause harm, and He is the All-Hearing, the All-Knowing, three times, no sudden calamity will befall him until morning. And whoever says it three times in the morning, no sudden calamity will befall him until evening.) 2. The Hadith of Abu Hurayrah, may Allah be pleased with him, that the Prophet, peace and blessings be upon him, said: (Had you said when you entered the evening: I seek refuge in the perfect words of Allah from the evil of what He has created, it would not have harmed you.) And for whoever says it three times in the evening, (no venomous creature would harm him that night).

Nevertheless, poison should not be used in challenges and debates, because it is inherently forbidden, and because it might harm a person, becoming a trial and a deterrent from the religion of Allah. For harm may occur despite reciting the invocation due to weak conviction or the presence of an impediment. Invocations are like a weapon that requires a strong wielder and the absence of an impediment for its effect to be realized.