Riyad as-Salihin 144
Ibn Mas'ud (May Allah be pleased with him) reported:
The Prophet (ﷺ) said, "Ruined are those who insist on hardship in matters of the Faith." He repeated this three times. [Muslim]
وعن ابن مسعود رضي الله عنه أن النبي صلى الله عليه وسلم قال‏:‏ ‏"‏هلك المتنطعون‏"‏ قالها ثلاثاً ‏"‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏