How is the funeral prayer performed for one whose Islam is unknown?

The Shaykh : And here is a question that has just come in from a questioner.

The questioner : He says that there are people among the apostates whose status is unknown, such as people who do not pray. It is well known that if a person dies while not praying, he is a disbeliever. It is not permissible to pray over him, nor to supplicate for mercy for him. It is not permissible for his family, who know that he died while not praying, to wash him or shroud him. Nor should they bring him to the Muslims.

The Shaykh : The Muslims do not pray over him. Rather, it is obligatory for them to take him out to a place

The questioner : and then dig a grave for him. They bury him in it, because he is a disbeliever. And Allah the Exalted said

The Shaykh : to the Prophet (peace and blessings be upon him)

The questioner : The Prophet (peace and blessings be upon him),

The Shaykh : over his grave? Why? This is because, unfortunately, there are people today who die while not praying, and a body is brought to a person and he is in doubt about it. So what prayer does he perform if a man is brought to him and he does not know whether he is a Muslim or not?
The answer to this is that we say that Ibn al-Qayyim, in his book *I'lam al-Muwaqqi'in*, mentioned that his Shaykh, Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him), had difficulties with certain issues in knowledge. He saw the Prophet (peace and blessings be upon him) in a dream and asked him about these issues, including the fact that Shaykh al-Islam Ibn Taymiyyah would be brought funerals of people he did not know whether they were Muslims or non-Muslims. The answer was: "You must make a condition, O Ahmad." Ahmad is the name of Shaykh al-Islam Ibn Taymiyyah. The Messenger (peace and blessings be upon him) said to him in the dream: "You must make a condition, O Ahmad."

The questioner : And the meaning of "You must make a condition"

The Shaykh : is that you make a condition in the supplication and say: "O Allah, if he was a believer, forgive him and have mercy on him," and so on. Making a condition in the supplication is permissible. The Qur'an says, and He the Exalted said, in the story of the two who swore falsely, that the woman said, and the man said, "And the curse of Allah be upon him if he is of the liars," and the woman said, "And the anger of Allah be upon her if she is of the truthful ones." And in the Sunnah, the Prophet (peace and blessings be upon him) narrated the story of the men of the cave who were trapped, and they sought nearness to Allah through their good deeds. They said in their seeking nearness: for Your sake . This is a conditional supplication, and conditional supplication is permissible. So this dream that Shaykh al-Islam saw is a dream supported by the Book and the Sunnah, and it is to be considered. Accordingly, if a funeral is brought to you and you do not know whether it is a Muslim or a non-Muslim, say: "O Allah, if he was a believer, forgive him and have mercy on him." And Allah, Blessed and Exalted is He, knows that.