Assalaamu alaykum. There is a hadith about a slave girl whom the Messenger of Allah, sallallahu ʻalayhi wa sallam, asked where "Allah" is, to which she replied, “In the heaven.” The Messenger said, “Set her free, she is a believer.” Could this be the base of a non-Muslim becoming a muslim today? For example, I would ask them where Allah is instead of reciting the Shahaadatayn (the two testimonies of faith: There is no God except Allah, and Muhammad is the Messenger of Allah).

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ʻalayhi wa sallam, is His slave and Messenger.

The scholars underlined that when a non-Muslim wishes to embrace Islam, he has to recite the Shahaadataan (the two testimonies of faith), and he is ruled to be a Muslim by reciting them. Hence, the person who is able to pronounce them must do so, and he is not declared a Muslim except if he pronounces them.

An-Nawawi said:

“The scholars of Hadeeth, Fiqh, and Kalaam (Scholastic theology) from Ahl As-Sunnah unanimously agreed that the believer who is deemed to be from the people of the Qiblah (prayer direction, meaning that he is a Muslim) and who shall not abide eternally in Hellfire is the one who believes in his heart in the religion of Islam with a strong decisive belief that is free from doubts and who uttered the two testimonies of faith. If one only utters one of the two testimonies of faith, he is not considered among the people of the Qiblah (i.e. he is not a Muslim) at all unless he is unable to utter it due to a defect in his tongue or because death overtook him before uttering them in full, or other reasons, in which case he is considered to be a Muslim. If he utters the two testimonies of faith, he is not required to state that he disassociates himself from all false religions that contradict Islam unless he belonged to the disbelievers who believed that the message of our Prophet, sallallahu ʻalayhi wa sallam, was sent to the Arabs only. If he had held that belief, he is not declared a Muslim unless he disassociates himself from it.”

As for admitting that Allah is in the heaven, then this is a belief held by the adherents of all religions. Accordingly, a person is not declared a Muslim merely on account of such a conviction. Apparently, that slave girl was already Muslim, and she was not a disbeliever whom the Prophet, sallallahu ʻalayhi wa sallam, declared to be Muslim on account of her saying that Allah is in the heaven. So there was nothing problematic about that incident.

Al-Khattaabi clarified this, saying:

“The hadeeth reads, ‘Free her; she is a believer.’ He, sallallahu ʻalayhi wa sallam, did not see any other sign indicating that she was a believer except for her statement when he asked her, ‘Where is Allah?’ and she replied, ‘In the heaven.’ He further asked her, ‘Who am I?’ She replied, ‘The Messenger of Allah.’ This was a question about the signs indicative of her faith and not a question about the foundation and reality of her faith. If a disbeliever comes to us wanting to embrace Islam and described his faith with what this slave girl said only, he is not declared a Muslim until he testifies that there is nothing worthy of worship but Allah and that Muhammad is the Messenger of Allah and disassociates himself from his false religion which he used to believe in. This is similar to a situation of a man and woman living in the same house and the man is asked about the woman and he replies that she is his wife and she confirms it; their declaration is accepted in this regard. The matter is not further investigated and they are not asked to present the marriage contract. However, if a man and woman want to get married, they are asked to fulfill the conditions for the validity of a marriage contract, such as the bride's Wali (legal guardian), witnesses, specifying the dowry, and so on. The same applies to the disbeliever if he is invited to embrace Islam; it is not sufficient that he says 'I am Muslim'; rather, he has to describe his faith with its due conditions. If someone claims to be a Muslim and we do not know whether he is a Muslim or a non-Muslim, we accept his word in this regard. The same applies if we see on him signs indicating that he is a Muslim, like his outward appearance or the like; he is declared a Muslim until we learn otherwise.”

Allah knows best.