Musnad Ahmad 26:108

Yahya ibn Sa'id narrated to us, Ibn Jurayj narrated to us, Sulayman ibn 'Atiq narrated to me, from Talq ibn Habib, from al-Ahnaf ibn Qays, from 'Abdullah ibn Mas'ud, from the Prophet, may Allah bless him and grant him peace, who said: "The *mutanatti'un* (those who are overly strict/excessive) are ruined," three times. Yahya said: In a long hadith.