ʿUyūn akhbār al-Riḍā
Hadith 286286 - وَبِإِسْنادِهِ عَنْ عَلِيِ عَلَيْهِ السَّلامُ قالَ: قالَالنَّبِيُ صَلَّى اللهُ عَلَيْهِ وَآلِهِ: يا عَلِيُّ لا تُتبِعِ النَّظَرَةَ النَّظرَةَ فَلَيْسَ لَكَ إِلاّ أَوَّل النَّظَرَةِ.
31-286 According to the same documentation, on the authority of Ali (a.s.), the Prophet (S) said, “O Ali! If you look upon an unfamiliar woman unintentionally, do not look again. Only that first unintentional look does not matter.”