Riyad as-Salihin

Hasan bin 'Ali (May Allah be pleased with them) said: I remember (these words) from Messenger of Allah (ﷺ): "Give up what is doubtful to you for that which is not doubtful; for truth is peace of mind and falsehood is doubt".

[At- Tirmidhi, who categorised it as Hadith Hasan Sahih].