Hadith 1090

حَدَّثَنَا مُحَمَّدُ بْنُ كَثِيرٍ، قَالَ‏:‏ أَخْبَرَنَا سُفْيَانُ، عَنْ أَبِي إِسْحَاقَ، عَنْ مُسْلِمِ بْنِ نَذِيرٍ قَالَ‏:‏ اسْتَأْذَنَ رَجُلٌ عَلَى حُذَيْفَةَ فَاطَّلَعَ وَقَالَ‏:‏ أَدْخُلُ‏؟‏ قَالَ حُذَيْفَةُ‏:‏ أَمَّا عَيْنُكَ فَقَدْ دَخَلَتْ، وَأَمَّا اسْتُكَ فَلَمْ تَدْخُلْ‏. ¤ وَقَالَ رَجُلٌ: أَسْتَأْذِنُ عَلَى أُمِّي؟ قَالَ: إِنْ لَمْ تَسْتَأْذِنْ رَأَيْتَ مَا يَسُوؤُكَ.
It is narrated from Muslim bin Nazeer (may Allah have mercy on him), he said that a man sought permission from Sayyiduna Hudhaifah (may Allah be pleased with him), so he peeked in and said: "May I come in?" Sayyiduna Hudhaifah (may Allah be pleased with him) said: "Your eye has already entered, only your body remains (so what is the need for permission now?)"

And a man asked: "Should I seek permission even to go to my mother?" He replied: "If you do not seek permission, you may see something that you would dislike to see."
Hadith Reference الادب المفرد / كتاب الاستئذان / 1090
Hadith Grading الألبانی: صحيح ، حسن
Hadith Takhrij «صحيح ، حسن : أخرجه ابن أبى شيبة : 26237 و الخرائطي فى اعتلال القلوب : 281 و أخرجه عبدالرزاق : 19421 و البيهقي فى الكبرىٰ : 97/7»