that 'Amr bin 'Abdullah bin Safwan informed him, that Kaladah bin Hanbal had informed him, that Safwan bin Umayyah sent him to bring some milk, colostrum, and Daghabis (a type of herb) to the Prophet ﷺ while he was in the upper valley. (He said): "I entered upon him without seeking permission nor giving Salam. The Prophet ﷺ said: 'Go back and say: As-Salamu Alaykum, may I enter?'" And that was after Safwan had accepted Islam." (Using translation from Tirmidhī 2710)   

أَخْبَرَهُ أَنَّ صَفْوَانَ بْنَ أُمَيَّةَ بَعَثَهُ فِي الْفَتْحِ إِلَى النَّبِيِّ ﷺ بِلَبَنٍ وَجَدَايَةٍ وَضَغَابِيسَ وَالنَّبِيُّ ﷺ بِأَعْلَى الْوَادِي قَالَ فَدَخَلْتُ عَلَيْهِ وَلَمْ أُسَلِّمْ وَلَمْ أَسْتَأْذِنْ فَقَالَ النَّبِيُّ ﷺ ارْجِعْ فَقُلِ السَّلَامُ عَلَيْكُمْ أَأَدْخُلُ؟ قَالَ وَذَلِكَ بَعْدَ أَنْ أَسْلَمَ صَفْوَانُ قَالَ عَمْرٌو فَأَخْبَرَنِي هَذَا الْخَبَرَ أُمَيَّةُ بْنُ صَفْوَانَ أَيْضًا وَلَمْ يَقُلْ أُمَيَّةُ سَمِعْتُهُ مِنْ كَلَدَةَ  

A man of Banu Amir told that he asked the Prophet ﷺ for permission (to enter the house) when he was in the house, saying: May I enter ? The Prophet ﷺ said to his servant: Go out to this (man) and teach him how to ask permission to enter the house, and say to him: "Say : Peace be upon you. May I enter?" The man heard it and said: Peace be upon you! May I enter ? The Prophet ﷺ permitted him and he entered. (Using translation from Abū Dāʾūd 5177)   

أَنَّهُ اسْتَأْذَنَ عَلَى النَّبِيِّ ﷺ فَقَالَ أألِجُ؟ فَقَالَ النَّبِيُّ ﷺ اخْرُجْ إِلَيْهِ فَإِنَّهُ لَا يُحْسِنُ الِاسْتِئْذَانَ فَقُلْ لَهُ فَلْيَقُلِ السَّلَامُ عَلَيْكُمْ أَأَدْخُلُ فَسَمِعْتُهُ يَقُولُ ذَلِكَ فَقُلْتُ السَّلَامُ عَلَيْكُمْ أَأَدْخُلُ؟ فَأَذِنَ لِي فَدَخَلْتُ