From Sahih Bukhari (Hadith 6586):
Narrated Ibn Al-Musaiyab:The companions of the Prophet (ﷺ) said, "Some men from my companions will come to my Lake-Fount and they will be driven away from it, and I will say, 'O Lord, my companions!' It will be said, 'You have no knowledge of what they innovated after you left: they turned apostate as renegades (reverted from Islam)
Reference: Bukhari 6586