Islam is very clear cut on prohibiting befriending any person of innovation. A number of unambiguous authentic Ahadith exist on this specific matter. Surprisingly however, many people don’t know the unambiguous evidence for this from the Qur’an. They also do not know that Allah mentioned the reason why we are prohibited from befriending them!
I’d like to share that verse of the Qur’an with you إن شاء الله. The proof that Allah prohibited befriending the people of innovation in the Quran is the Ayah:
وَمِنَ ٱلنَّاسِ مَن يُجَٰدِلُ فِى ٱللَّهِ بِغَيۡرِ عِلۡمٍ وَيَتَّبِعُ كُلَّ شَيۡطَٰنٍ مَّرِيدٍ كُتِبَ عَلَيۡهِ أَنَّهُۥ مَن تَوَلَّاهُ فَأَنَّهُۥ يُضِلُّهُۥ وَيَهۡدِيهِ إِلَىٰ عَذَابِ ٱلسَّعِيرِ
“There are some people who dispute concerning Allah without knowledge, and they follow every rebellious devil ۞ It has been decreed that whoever befriends such a person, he will misguide him and lead him to the punishment of the Blazing Fire.”
Surah Al-Hajj 21:3-4