In the name of Allah the Most Gracious the Most MercifulRuling of calling someone a disbeliever because they do not pray
By Shaykh Muhammad ibn Saalih al-’Uthaymeen may Allah have mercy on him
Question: An argument broke out between my brother and myself, I then said to him, “O Kaafir [disbeliever]” because he does not pray. What is the ruling of my statement?
Answer: The one who does not pray is a disbeliever and it takes him out of the religion. If he dies [upon that state] then he dies upon disbelief, and on the Day of Resurrection he will be with Fir’awn, Qarun, Haamaan, and Ubay bin Khalaf. However, it shouldn’t be said to a specific person “O Kaafir” until evidence is established and clarified to that person that [abandoning the prayer] is an act of disbelief.
As for what occurred between the questioner and his brother then we say that this action should have not occurred. Rather, when the questioner talks to his brother he should do so with normal speech. He should clarify to his brother that abandoning prayer is disbelief and if he persists on abandoning the prayer then he is a disbeliever. As for describing him with kufr when arguing, then this should not occur.
And the summary of my response is: the one who abandons prayer is a disbeliever who has left the religion, and if one dies in that state then they are not from the believers. They will be gathered on the Day of Resurrection with Fir’awn, Qarun, Haamaan, and Ubay bin Khalaf. However, in times of argument we should not describe anyone with kufr by saying, “O Kaafir”. Rather we clarify to them with normal speech that abandoning prayer is disbelief and if they continue upon this then they are disbelievers, hoping that Allah will guide them and return them back to the religion.
Source: Fataawa Nur ‘ala ad-Darb 1/309
Translated by: Abu Awzaa’ee AbdusSalaam
الفقير الى الله