Ruling on teaching false religions to children
Question

                Im a student, becoming a teacher in religion to teach children. I live in Europe, in a Christian country, but my studies teaches the five main world religions (Islam, Christianity, Judaism, Hinduism and Buddhism). I've never thought that it could be haram to teach other religions to children, because I don't see non-Islamic religions as the truth and I will never tell it is. I believe children need to know what other people believe in this world.

However, many people have been telling me my studies are haram and it's definitely haram to teach to other children, especially muslim children. I've been searching, but I couldn't find any source clarifying anything. I hope you can clarify it. Thank you very much in advance!
Praise be to Allah.
    
    The basic principle is that it is not permissible to study or 
    teach the distorted Scriptures, false religions or schools of thought that 
    are contrary to the truth, unless that is done with the aim of teaching 
    people that they are corrupt and false, and that they are contrary to reason 
    and common sense, and contrary to the religion of truth which Allah, may He 
    be glorified, has chosen for His slaves, namely Islam. In addition to that, 
    the one who is studying that should also have sound knowledge of the truth 
    and the ability to distinguish truth from falsehood, error from right 
    guidance, and there should be no fear that he will be tempted or confused by 
    that. This kind of study should be limited to specialists who it is hoped 
    will play a role in combatting these distorted and devilish religions; the 
    door should not be left open to everyone, especially the common folk and 
    children, lest that create in them doubts and uncertainty about their 
    religion. It says in Haashiyat Ibn ‘Aabideen (1/175): We were 
    instructed not to look into any of that, whether it was transmitted to us by 
    the disbelievers or by those among them who became Muslim. End quote. 

    
    In Kashshaaf al-Qinaa‘ ‘an Matn al-Iqnaa‘ (1/434) it 
    says: It is not permissible to read the books of the People of the Book – 
    this was stated by Imam Ahmad – because the Prophet (blessings and peace of 
    Allah be upon him) got angry when he saw ‘Umar carrying a page of the Torah, 
    and he said to him: “Are you doubting, O son of al-Khattab?” … It is not 
    permissible to read the books of those who follow innovation or the books 
    that contain both truth and falsehood, or to narrate them, because that 
    comes under the heading of corrupting beliefs. End quote. 

    
    Al-Haafiz Ibn Hajar (may Allah have mercy on him) said, when 
    discussing this issue – namely reading the books of the People of the Book: 
    With regard to this issue, it is more appropriate to differentiate between 
    the one whose faith is not deeply-rooted, in which case it is not 
    permissible for him to read any of those books, in contrast to the one whose 
    faith is deeply rooted, for whom it is permissible to do so, especially when 
    there is a need to refute the arguments of those whose view is opposed to 
    the truth. That is indicated by the fact that the imams (leading scholars) 
    of the past and present quoted from the Torah and challenged the Jews to 
    believe in Muhammad (blessings and peace of Allah be upon him) on the basis 
    of what they quoted from their books. If they did not believe that it is 
    permissible to read it, they would not have done that and they would all 
    have reiterated this view.

    
    End quote from Fath al-Baari by Ibn Hajar, 13/525 

    
    Shaykh Ibn Baaz (may Allah have mercy on him) was asked: Is 
    it permissible for us to read the books of religions other than Islam, out 
    of a desire to study and learn about other religions? He replied: That is 
    not appropriate. It is not appropriate to read the Torah or the Gospel or 
    any other books, because that may lead to doubt, and it was narrated from 
    the Messenger (blessings and peace of Allah be upon him) that when he saw 
    ‘Umar reading a page of the Torah, he said: “Are you doubting, O son of al-Khattab? 
    I have brought it to you white and pure; if Moosa were alive he could not 
    but follow me.” What is meant is that the Muslim should not read other 
    books, such as the Torah, the Gospel or any others, except in the case of 
    those who need to read them, such as scholars who want to refute the Jews 
    and Christians from their own books. If there is a need to do so, the 
    scholar who is refuting them and highlighting their falsehood may read their 
    books so that he may refute them on that basis. In that case there is 
    nothing wrong with doing that when there is a need for it, in the case of 
    those who have knowledge and insight.

    
    End quote from the Shaykh’s website


    http://www.binbaz.org.sa/mat/10748 

    
    If this is the ruling for adults, then it is more applicable 
    in the case of children, because their reasoning is still immature, so 
    teaching them these religions is a wrong action in which there is nothing 
    good. You will never be allowed, whilst teaching, to criticize these false 
    religions and highlight their falseness; even if this is allowed, children 
    will never be able to understand that, because specious arguments and 
    refutation thereof will be above their level of understanding. 

    
    And Allah knows best.