[2] You Desire a sound heart? Then keep Away From Ahlul Bidah [Rationalists and Philosophers Disguised as Muslim Intellectuals and advisers during times of Fitan]
Ibn Abbaas (radiyallaahu-anhumaa) said:
لا تجالس أهل الأهواء فإن مجالستهم ممرضة للقلوب
Do not sit with the people of desires (i.e. ahlul bidah) for indeed sitting with them will cause sickness to the hearts.
[Al-Ibaanah 2/438]