Is it necessary to declare belief with the tongue?
To declare belief with the tongue is not a necessity of belief. If a person does not express his belief by tongue, he will be regarded a believer by accepting it with the heart. However, how can we know about the belief of a person in his heart if he does not declare it with his tongue? Therefore, it is necessary to declare belief with the tongue so that Muslims can witness his belief and treat his dead body as a Muslim when he dies. Therefore, the two fundamentals of belief are expressed as “acceptance with the heart and declaration by the tongue”. Here, declaration by the tongue is not the essential fundamental but it is necessary to witness a person’s belief and to accept him as a believer. Praying in the congregation, carrying out a religious obligation are like declaration with the tongue; actually they are even stronger than it. Our Prophet said the following regarding the issue:
“Witness the belief of a person who attends the mosque because Allah says, ” The Mosques of Allah shall be maintained only by those who believe in Allah and the Last Day, perform as-salat (prayers), and give zakat (alms).’ (at-Tawba, 18).”
It is not objectionable by religion to deny one’s belief or to utter words contrary to belief under compulsion or due to a similar excuse with the tongue not with the heart since declaration with the tongue is not the essential fundamental of belief. A person who is forced to do so does not become an unbeliever; he is regarded a believer since he preserves his acceptance with the heart.
Accordingly, during the Age of Happiness, Ammar Bin Yasir, a companion of the Prophet, could not endure the oppression and tortures, and denied his belief with the tongue; so, he got rid of the tortures he was exposed to.
Our Prophet approved what he had done; the Prophet said that the denial of belief with the tongue under oppression and violence would not harm belief when the heart is full of belief. It was stated in the Quran that the denial under compulsion would not make a person unbeliever. (an-Nahl 16/106)