Sahih Muslim 2036 a
Abu Mas'ud Ansari reported that a person from the Ansar who was called Abu Shu'aib had a slave who was a butcher (by profession). He (Abu Mas'ud) saw Allah's Messenger (ﷺ) and found signs of hunger on his face. He said to the servant:
0 ye, prepare for us food sufficient for five persons, for I intend to invite Allah's Apostle (ﷺ) who would be the fifth amongst the five. He (the narrator) reported that he then prepared the food and came to Allah's Apostle (ﷺ) and invited all the five (including him) who was the fifth amongst them to the feast. A man followed him and when Allah's Apostle (ﷺ) reached the door, he said: This man has followed us; if you like you may permit him (to join the meal) and if you like he can go back. Thereupon the person said: Allah's Messenger, I permit him.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَعُثْمَانُ بْنُ أَبِي شَيْبَةَ، - وَتَقَارَبَا فِي اللَّفْظِ - قَالاَ حَدَّثَنَا 
 جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ أَبِي وَائِلٍ، عَنْ أَبِي مَسْعُودٍ الأَنْصَارِيِّ، قَالَ كَانَ رَجُلٌ مِنَ الأَنْصَارِ
 يُقَالُ لَهُ أَبُو شُعَيْبٍ وَكَانَ لَهُ غُلاَمٌ لَحَّامٌ فَرَأَى رَسُولَ اللَّهِ صلى الله عليه وسلم فَعَرَفَ فِي
 وَجْهِهِ الْجُوعَ فَقَالَ لِغُلاَمِهِ وَيْحَكَ اصْنَعْ لَنَا طَعَامًا لِخَمْسَةِ نَفَرٍ فَإِنِّي أُرِيدُ أَنْ أَدْعُوَ النَّبِيَّ
 صلى الله عليه وسلم خَامِسَ خَمْسَةٍ ‏.‏ قَالَ فَصَنَعَ ثُمَّ أَتَى النَّبِيَّ صلى الله عليه وسلم فَدَعَاهُ
 خَامِسَ خَمْسَةٍ وَاتَّبَعَهُمْ رَجُلٌ فَلَمَّا بَلَغَ الْبَابَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏
"‏ إِنَّ هَذَا
 اتَّبَعَنَا فَإِنْ شِئْتَ أَنْ تَأْذَنَ لَهُ وَإِنْ شِئْتَ رَجَعَ ‏"‏ ‏.‏ قَالَ لاَ بَلْ آذَنُ لَهُ يَا رَسُولَ اللَّهِ ‏.‏