Abu Dharr (May Allah be pleased with him) reported:
I heard the Messenger of Allah ﷺ saying: "A person who attributes his fatherhood to anyone other than his real father, knowing that he is not his father, commits an act of disbelief. And he who makes a claim of anything which in fact does not belong to him, is none of us. He should make his abode in Hell, and he who labels anyone as disbeliever or calls him the enemy of Allah and he is in fact not so, his charge will revert to him."

[Al-Bukhari and Muslim].

وعن أبي ذر رضي الله عنه أنه سمع رسول الله ﷺ يقول: “ليس من رجل ادعى لغير أبيه وهو يعلمه إلا كفر، ومن ادعى ما ليس له، فليس منا، وليتبوأ مقعده من النار، ومن دعا رجلاً بالكفر، أو قال: عدو الله، وليس كذلك إلا حار عليه” ((متفق عليه وهذا لفظ رواية مسلم)).