عَنْ أَنَسِ بْنِ مَالِكٍ رَضِيَ اللَّهُ عَنْهُ قَالَ كُنْتُ أَخْدُمُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَكُنْتُ أَدْخُلُ عَلَيْهِ بِغَيْرِ إِذْنٍ فَجِئْتُ ذَاتَ يَوْمٍ فَدَخَلْتُ عَلَيْهِ فَقَالَ يَا بُنَيَّ إِنَّهُ قَدْ حَدَثَ أَمْرٌ فَلَا تَدْخُلْ عَلَيَّ إِلَّا بِإِذْنٍ
Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that I was assigned to the service of the Noble Prophet (peace and blessings be upon him), so I used to come to you without permission. One day, I entered (as per routine), so the Prophet (peace and blessings be upon him) said: Dear son! A new command has been enforced, so do not come to me without permission.