Uttering Words of Kufr (disbelief) Ignorantly
Question

                What is the ruling on one who says “I am a communist” without understanding it?
Praise be to Allah.
    Words matter according to the great 
    religion of Allah: by means of a word a person speaks, Allah may raise him 
    in status, and by means of a word he speaks he may be doomed to Hell. 

    Allah says (interpretation of the 
    meaning):

    “Not a word does he (or she) utter but 
    there is a watcher by him ready (to record it)” [50:18] 

    Al-Bukhaari and Muslim narrated from Abu 
    Hurayrah that the Messenger of Allah (blessings and peace of Allah be upon 
    him) said: “ A person may speak a word, not realizing what he is saying, and 
    he will fall because of it into the Fire further than the distance between 
    the East and West.” 

    Al-Tirmidhi narrated in a report which he 
    classed as saheeh (authentic), that Bilaal ibn al-Haarith said: I heard the 
    Messenger of Allah (blessings and peace of Allah be upon him) say: “One of 
    you may speak a word that pleases Allah, and not know how far it reaches, 
    but Allah will decree that He is pleased with him until the Day he meets 
    Him. And one of you may speak a word that angers Allah, and not know how far 
    it reaches, but Allah will decree that He is angry with him, until the Day 
    he meets Him.”   

    Al-Nasaai narrated from ‘Abd-Allah ibn 
    Buraydah that his father said: the Messenger of Allah (blessings and peace 
    of Allah be upon him) said: “Whoever says ‘I have nothing to do with Islam’ 
    and is lying, he is as he said, and if he is telling the truth, he will 
    never come back to Islam soundly.” 

    Communism is a kind of atheism that is 
    based on denial of the existence of God and veneration of the material, 
    which it regards as the basis of all things. It does not value religion in 
    general, any religion. Rather they regard religion as people's problems or 
    as they say, the opium of the people, meaning that it distracts them from 
    their material aims which form the basis of their ideology. 

    Undoubtedly this is one of the most 
    dangerous kinds of kufr in the modern age, by which many people have been 
    deceived and which has persecuted many people of religious commitment and 
    faith. 

    Undoubtedly what is required of everyone 
    who hears of this ideology and finds out about it is to reject it and to 
    disavow himself of it and of its people before Allah. Veneration of this 
    ideology, belief in it, promotion of it or love of it and its people cannot 
    coexist with faith in the heart of anyone. 

    The one who joins them when he is aware of 
    them and of the misguidance that they follow is a disbeliever in Allah the 
    Almighty. If the one who says these words is ignorant of the basis of their 
    ideology or has been deceived by their claims with regard to social and 
    economic matters and their claims to care for the poor, to help them and to 
    guarantee their rights, then he must be told of the real nature of this 
    ideology and the danger it poses to religious commitment and faith, and that 
    Allah has made His slaves independent, by means of the laws that He has 
    revealed to them, of the need for any religion, sect or ideology  other than 
    that. 

    We suggest that any advice given to those 
    who have been deceived by this ideology should be given in a kind and gentle 
    manner, debating in a good way and explaining the evidence for that from 
    sharee’ah (Islamic law). The one who engages in that should have sufficient 
    understanding of this kafir un-Islamic) ideology and be skilled in debating 
    and arguing, because most of those who are deceived by this ideology are 
    very capable in argument and debate. 

    If he is indeed ignorant of this group and 
    its origins, or he is ignorant of how it conflicts with the faith that is 
    required of people, then he is excused for his ignorance. But if he 
    persists, after things are explained to him, then he is a kafir 
    (disbeliever) and an apostate. 

    We ask Allah to protect our faith and to 
    help us avoid fitnah (trial and tribulation), both apparent and hidden.