Muslim Woman Having Close Ties with Christian Woman
2-1-2020 | IslamWeb
Question:
A Muslim woman in her twenties has a very good Christian (female) friend. She told even that she is her best friend. They talk about everything and they spend a lot of time together. This Muslim woman started lately to read the Quran and she found out that she is not allowed to have infidels as friends. Now she fears that she has apostatised due to the fact that she has a Christian friend and she wants very much to repent from this sin yet she does not want to end the friendship with Caroline because she is her best friend. She does not know what to do. What is the best solution to this problem? Should she move away and break off relations with her friend for good? As of now she cannot imagine doing this but yet she wants to be a good Muslima. What can I tell her?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
Firstly, it should be known that Islam preaches kindness towards all people, and it does not forbid showing kindness to the disbelievers as long as they are not at war with us on account of religion. Allah, The Almighty, Says (what means): {Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes - from being righteous toward them and acting justly toward them. Indeed, Allah loves those who act justly.} [Quran 60:8]
It has been authentically reported on the authority of Anas 
that a young Jewish boy, who was in the service of the Prophet fell ill. The Prophet went to visit him, sat down by his head and said to him: "Embrace Islam." The little boy looked at his father, who was sitting beside him. Thereupon, the father said: “Obey Abul-Qaasim [i.e. the Messenger of Allah ].” So, the little boy embraced Islam, and the Prophet went out saying: “Praise be to Allah Who has saved him from Hellfire.” [Al-Bukhaari]
However, a Muslim should be keen on keeping the company of righteous people; Allah, The Almighty Says (what means): {Close friends, that Day, will be enemies to each other, except for the righteous.} [Quran 43:67] Abu Sa‘eed narrated that the Prophet said: "Do not accompany except a believer, and do not serve your food except to a pious person." [Abu Daawood; Al-Albaani: Hasan (sound)]
There is no doubt that a person is influenced by his companion in terms of his morals and character and, therefore, a Muslim is enjoined to keep the company of righteous people and is forbidden from keeping the company of evil ones, and it is even prohibited to take non-Muslims as allies. Allah, The Exalted, Says (what means): {You will not find a people who believe in Allah and the Last Day having affection for those who oppose Allah and His Messenger, even if they were their fathers or their sons or their brothers or their kindred…} [Quran 58:22]
So, it is incumbent on this sister to limit her mixing with that woman and to reduce the time she spends with her. We mean here mixing with her at times when she commits sins as well as mixing with her while harboring affection for her. As to mixing with her due to a need, like interactions at the workplace and the like, there is nothing wrong with that. The same applies to communication intended for the purpose of calling her to Islam. Rather, it is a good thing, on condition that the one calling others to Islam possesses adequate religious knowledge that shields him from their malicious misconceptions. Allah, The Exalted, Says (what means): {And when you see those who engage in [offensive] discourse concerning Our verses, then turn away from them until they enter into another conversation. And if Satan should cause you to forget, then do not remain after the reminder with the wrongdoing people.} [Quran 6:68] As-Sa‘di 
said in his Tafseer: "(A Muslim) should not attend such gatherings where people indulge in falsehood. He has to maintain this attitude until the discussion in such gatherings shifts to other topics, in which case the mentioned forbiddance is eliminated. If attending such gatherings yields a benefit, it is enjoined; otherwise, it is neither beneficial nor enjoined." [End of Quote] This Muslim sister is advised to call her female companion to Islam and to mix with her less if she does not respond to her call. The basic principle is that the disbeliever should be forsaken except for a benefit; nevertheless, merely keeping the company of a disbeliever is not considered an act of apostasy that takes one out of the fold of Islam.
For more benefit on keeping ties with non-Muslims and being just with them, please refer to Fataawa 369664, 384016, 395743 and 88293.
Allah Knows best.