What is the ruling regarding a Muslim who had doubts in the religion, is he a non-Muslim or a hypocrite? Allaah said "Only those are the believers who have believed in Allaah and His Messenger and afterward doubt not but strive with their wealth and their lives for the Cause of Allaah. Those they are the truthful "(Al-Hujuraat 49:15). Also the Prophet said "Bear witness that there is no god except Allaah and that I am the Messenger of Allaah, for no person meets Allaah with these two, not doubting in them, but he will enter paradise.' What is the ruling on one who had doubts for a moment and one who has doubts about the Deen all his life (Allaah forbid)?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Doubting the principles of faith and the principles of Islam takes the person out of the fold of Islam. A person who doubts is not a believer, as being firm upon belief is a condition for the validity of belief. A person who doubts, neither confesses to the truth nor is he sure about it. Allaah says (which means): {Only those are the believers who have believed in Allaah and His Messenger, and afterward doubt not…}[Quran 49:15]. For more details, please refer to Fatwa: 88276.

Therefore, not doubting is a condition for the validity of belief in Allaah and His Prophet because the person who doubts is a hypocrite. Allaah says (which means): {Only those would ask permission of you who do not believe in Allaah and the Last Day and whose hearts have doubted, and they, in their doubt, are hesitating.}[Quran 9:45].

The Prophet said: "I bear witness that there is none worthy of worship except Allaah and I bear witness that I am the Messenger of Allaah, no one meets his Lord with this testimony not doubting in it except that he will be admitted to Paradise." [Muslim]

In this narration, the Prophet conditioned entering Paradise on uttering these testimonies with a content heart and without being in doubt. So if the condition is not fulfilled, the person will not enter Paradise. However, one should differentiate between being content with this doubt as this takes the person out of the fold of Islam, and between the whispers of the devil which a person is not content with and which he tries to repel from his heart, as this is not disbelief [this does not take the person out of the fold of Islam]. The fact that a person hates these whispers and tries to repel them from his heart proves his correct belief.

Some companions came to the Prophet and asked him: "We find in our hearts what we consider as a very serious matter and a great sin to talk about." The Prophet said: "Do you really feel this? They replied: "Yes." He remarked: "That is the essence of correct belief." [Muslim]

Please refer to Fatwa: 88597 about the whispers which do not affect the belief and Fatwa: 85823 about how to treat doubts and whispers.

Finally, it should be noted that the person who is content with this doubt, we seek the Refuge of Allaah from that, is not like the person who has these whispers and is not content with them. 

Allaah Knows best.