Al-Tabari reported: Abu Darda, may Allah be pleased with him, said, “Goodness is in peace of mind and evil is in doubt. Leave what makes you doubt for what does not make you doubt.”
Source: Tafsīr al-Ṭabarī 67:15
عن الطبري وَقَالَ أَبُو الدَّرْدَاءِ رضي الله عنه الْخَيْرُ فِي طُمَأْنِينَةٍ وَالشَّرُّ فِي رِيبَةٍ فَذَرْ مَا يُرِيبُكَ إِلَى مَا لَا يُرِيبُكَ
67:15 تفسير الطبري