What is the ruling on insulting and reviling a preacher who debates Christians, and argues in doing so that Abu Bakr Al-Siddiq (may Allah be pleased with him) said to the disbeliever: "Suck the clitoris of Al-Lat," and the Messenger of Allah (peace and blessings be upon him) did not forbid him from doing so?

The fundamental principle is that a Muslim should adhere to good manners and abandon bad ones, for the Prophet, peace and blessings be upon him, was neither obscene nor vulgar. He said, "A believer is not a slanderer, nor a curser, nor an obscene speaker, nor a foul-mouthed person." What was uttered by Abu Bakr Al-Siddiq, may Allah be pleased with him, was in a specific context and is not the general rule for discourse with disbelievers. The fundamental principle is to invite them with wisdom and good admonition.

It is not permissible to curse a disbeliever with the phrase "son of a whore," because it is a clear accusation of fornication. Even if it does not necessitate a prescribed punishment (hadd) on the Muslim because the accused woman is a disbeliever, it is still a sin that warrants disciplinary punishment (ta'zir), for honor and reputation are to be preserved.

One must be careful not to curse whom the Christians call Jesus, because they mean 'Isa, peace be upon him. One must also be careful not to curse the religion of the Christians, because it may lead to them cursing the religion of the Muslims.