Sahl bin Saad reported,

A man peeped into the Prophet's ﷺ room through a gap in the curtain of his chamber while the Prophet ﷺ held a comb in his hand. The Prophet ﷺ said, "Had I known you were watching me before I came upon you, I would have thrust this comb into your eye. Permission to enter was prescribed only because of the gaze."

حدثنا عبد الرزاق حدثنا معمر عن الزهري

عن سهل بن سعد

أن رجلا اطلع على النبي ﷺ من ستر حجرته وفي يد النبي ﷺ مدرى فقال لو أعلم أن هذا ينظرني حتى آتيه لطعنت بالمدرى في عينه وهل جعل الاستئذان إلا من أجل البصر