Arabic (Original)
حَدَّثَنَا سُفْيَانُ عَنِ الزُّهْرِيِّ عَنْ سَهْلِ بْنِ سَعْدٍ اطَّلَعَ رَجُلٌ مِنْ جُحْرٍ فِي حُجْرَةِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَمَعَهُ مِدْرًى يَحُكُّ بِهِ رَأْسَهُ فَقَالَ لَوْ أَعْلَمُكَ تَنْتَظِرُ لَطَعَنْتُ بِهِ عَيْنَكَ إِنَّمَا جُعِلَ الِاسْتِئْذَانُ مِنْ أَجْلِ الْبَصَرِ.
English Translation
Sufyan told us, from az-Zuhri, from Sahl ibn Sa'd: A man peeped through a hole into the chamber of the Prophet, peace and blessings be upon him, while he had a comb-like implement with which he was scratching his head, and he said: Had I known you were watching, I would have poked your eye with it. Seeking permission to enter was only prescribed because of the sight.