﴿ وَأَمَّا ٱلْغُلَٰمُ فَكَانَ أَبَوَاهُ مُؤْمِنَيْنِ فَخَشِينَآ أَن يُرْهِقَهُمَا طُغْيَٰنًۭا وَكُفْرًۭا ﴾

“"And as for that young man, his parents were [true] believers - whereas we had every reason to fear that he would bring bitter grief upon them by [his] overweening wickedness and denial of all truth:”

Please check ayah 18:81 for complete tafsir.