He has a Raafidi friend; can he remain friends with him?
Question

                I have a friend who is from Ahl al-Sunnah wa’l-Jamaa’ah, and he has a Shi’i friend. I would like to find out the ruling on being friends with people from different madhhabs. Please note he has advised him – as he told me – to follow the madhhab of the saved group, but to no avail. What is the ruling on their friendship?.
Praise be to Allah.You should 
    advise your friend to avoid making friends with the followers of bid’ah, 
    especially extreme bid’ahs such as the Shi’ah and Raafidis, because being 
    friends with them poses a danger to the Muslim’s religious and worldly 
    interests. The danger to his religious interests involves the specious 
    arguments that this Raafidi may present to him, causing him to doubt his 
    religion, and the danger to his worldly interests involves the hatred that 
    the Raafidi may feel towards Ahl al-Sunnah and he may strive to harm them in 
    whatever ways he can. 
There are 
    ahaadeeth from the Prophet  (peace and blessings of Allaah be upon him) 
    which encourage us to choose our friends wisely, because of the influence 
    that a friend may have on one’s attitude and religious commitment. These 
    ahaadeeth include the following: 
1 – It was 
    narrated from Abu Sa’eed al-Khudri that the Messenger of Allaah  (peace 
    and blessings of Allaah be upon him) said: “Do not keep company with anyone 
    but a believer and do not let anyone eat your food but one who is pious.” 
Narrated by 
    al-Tirmidhi (2395)and Abu Dawood (4832); classed as saheeh by al-Albaani in
    Saheeh al-Tirmidhi. 
2 – It was 
    narrated that Abu Hurayrah (may Allaah be pleased with him) said: The 
    Messenger of Allaah  (peace and blessings of Allaah be upon him) said: 
    “A man will follow the way of his close friends, so let one of you look to 
    whom he takes as a close friend.” 
Narrated by 
    al-Tirmidhi (2378) and Abu Dawood (4833). Classed as saheeh by al-Albaani in
    Saheeh al-Tirmidhi. 
Al-Khattaabi 
    (may Allaah have mercy on him) said: 
Do not take 
    as a close friend anyone but one whose religious commitment and 
    trustworthiness you are pleased with, for if you take him as a close friend, 
    he will lead you to his religion and madhhab, so do not risk losing your 
    religious commitment and expose yourself to danger by taking as a close 
    friend one whose religious commitment and madhhab you are not pleased with. 
    End quote. 
Al-‘Azlah 
    (p. 141) 
Ibn ‘Abd 
    al-Barr (may Allaah have mercy on him) said:  
What this 
    means – and Allaah knows best – is that a man will get used to what he sees 
    of his friend’s actions. Hence he is commanded to make friends only with 
    those whose actions are only good and permissible.  
What this 
    means is that a person should not mix with those who will make him do and 
    believe things that are not praiseworthy. As for one with whom there is no 
    such danger, there is nothing wrong with making friends with him. End 
    quote. 
Bahjat 
    al-Majaalis (2/751). 
The salaf 
    said a great deal warning against making friends with the followers of 
    bid’ah. For example: 
1 – Shaykh 
    al-Islam Ibn Taymiyah (may Allaah have mercy on him) narrated that Abu 
    Yoosuf, the student of Abu Haneefah, said: 
No one among 
    Ahl al-Sunnah wa’l-Jamaa’ah should mix with anyone from among the people of 
    whims and desires so that he makes friends with him and becomes his close 
    confidante, lest he causes him to slip or causes others to slip because of 
    this friendship. 
Majmoo’ 
    al-Fataawa (16/475)  
2 – Abu 
    Dawood al-Sijistaani (may Allaah have mercy on him) said: 
I said to 
    Abu ‘Abd-Allaah – Ahmad ibn Hanbal – I see a man from Ahl al-Sunnah with a 
    man from the followers of innovation; should I stop speaking to him? He 
    said: No, unless you know that the man whom you saw with him is a follower 
    of innovation. If he stops speaking to him then speak to him, otherwise 
    regard them as both being the same. 
Tabaqaat 
    al-Hanaabilah (1/160). 
And Allaah 
    knows best.