Is it permissible to bargain one's religion by saying to a Christian: "If my religion is true, you will become a Muslim, and if you prove to me that your religion is true, I will become a Christian"?

It is not permissible for a Muslim to say the phrase "perhaps we or you are on guidance or misguidance" out of doubt or suspicion regarding the religion. However, it is permissible to say it in the context of argumentation and disputation, as a way of condescending to the opponent and being gentle with him, enticing him to acknowledge the truth. This is one of the legitimate methods for establishing proof against those who disagree. Examples of this in the Holy Quran include:

1. The Almighty's saying: ﴿Say, "Who provides for you from the heavens and the earth?" Say, "Allah. And indeed, we or you are either on guidance or in manifest error."﴾ 2. The Almighty's saying: ﴿Say, "If the Most Merciful had a son, then I would be the first of His worshipers."﴾

This is a method of establishing proof and denying offspring for Allah, and the speech takes the form of doubt in phrasing, but not in reality, for a kind of leniency and to curb obstinacy.