It goes without saying that Almighty Allah has created people for the very aim of worshipping Him. Some people, however, turned a deaf ear to this Divine call, and, adding insult to injury, extended their evil deed to others by forcing them to commit disbelief. Being the religion of mercy, Islam makes it clear that uttering the word of disbelief while is one is in a state of duress does not render him a disbeliever, so long as his heart is firm in faith.
Discussing this point, late Dr. Ahmad Ash-Sharabaasi (may Allah have mercy on his soul), professor at Al-Azhar University, says: “Allah Almighty says: “Whoso disbelieveth in Allah after his belief – save him who is forced thereto and whose heart is still content with the Faith – but whoso findeth ease in disbelief: On them is wrath from Allah. Theirs will be an awful doom.” (An-Nahl: 106)
This Qur’anic verse points out that there is a difference between a person uttering the words of disbelief just as a matter of lip service and uttering them out of full conviction. This leads to saying that a person who utters the words of disbelief (without really intending to commit kufr) just as is the case with a person under duress, is not considered to be a disbeliever. That is why the Holy Qur’an differentiates between such a person and others who shift completely to disbelief. Almighty Allah says: “save him who is forced thereto and whose heart is still content with the Faith”
It is recorded in the books of Sirah (the Prophet’s Biography) that Bilal bin Abu Rabah gave the best example in perseverance and proved reluctant to the calls of polytheists and never danced to his captor’s tune. He did not utter the words of disbelief. The more torment they poured on his body, the more steadfast he got; he never gave up reiterating: “(Allah) He is One! He is One! He is One.” However, Bilal was unique in this regard. During the lifetime of the Prophet, peace and blessings be upon him, some Muslims were forced to utter words of disbelief, but the words did not sink into their hearts.
In his exegesis of the Qur’an, Imam Ar-Razi recorded that when the polytheists persecuted and tortured `Ammar ibn Yasir, he could not stand the torment and thus was forced to utter the words of Kufr. Thereupon, it was said to the Prophet, peace and blessings be upon him: “O Messenger of Allah! `Ammar has turned a disbeliever.” The Prophet said: “No, `Ammar is filled with faith; and faith has become his flesh and blood.” `Ammar came to the Prophet while shedding tears. Whereupon, the Prophet, peace and blessings be upon him, wiped his tears and comforted him saying: “If they returned to their deed (i.e. torturing you), then return to your saying (i.e. the words of disbelief).”
According to the exegetes, uttering the words of disbelief when one is under extreme pain and unbearable torture (while faith is reposed in one’s heart) does not take one out of the fold of Islam.
Right after the previous verse, we read: “Then lo! thy Lord – for those who became fugitives after they had been persecuted, and then fought and were steadfast – lo! thy Lord afterward is (for them) indeed Forgiving, Merciful.” (An-Nahl: 110)

The verse makes it clear that such a person should sincerely turn to Allah in repentance. He should seek the protection of His Lord by showing obedience and offering acts of worship and abstaining from Allah’s prohibitions. He should strive in the cause of Allah as much as he could. He should show persistence while offering acts of obedience. In this way, Allah will forgive his sins and guide him to all that which is good for verily Allah is the All-Forgiving, All-Compassionate.”

Almighty Allah knows best.