كتاب الإيمان
1  
The Book of Faith
(43)
Chapter: The Saying of the prophet (saws): "Whoever deceives us is not one of us."
(43)
باب قَوْلِ النَّبِيِّ - صلى الله تعالى عليه وسلم - ‏"‏ مَنْ غَشَّنَا فَلَيْسَ مِنَّا ‏"‏
Sahih Muslim 102

It is narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) happened to pass by a heap of eatables (corn). He thrust his hand in that (heap) and his fingers were moistened. He said to the owner of that heap of eatables (corn):

What is this? He replied: Messenger of Allah, these have been drenched by rainfall. He (the Holy Prophet) remarked: Why did you not place this (the drenched part of the heap) over other eatables so that the people could see it? He who deceives is not of me (is not my follower).
وَحَدَّثَنِي يَحْيَى بْنُ أَيُّوبَ، وَقُتَيْبَةُ، وَابْنُ، حُجْرٍ جَمِيعًا عَنْ إِسْمَاعِيلَ بْنِ جَعْفَرٍ، - قَالَ ابْنُ أَيُّوبَ حَدَّثَنَا إِسْمَاعِيلُ، - قَالَ أَخْبَرَنِي الْعَلاَءُ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، ‏.‏ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم مَرَّ عَلَى صُبْرَةِ طَعَامٍ فَأَدْخَلَ يَدَهُ فِيهَا فَنَالَتْ أَصَابِعُهُ بَلَلاً فَقَالَ ‏"‏ مَا هَذَا يَا صَاحِبَ الطَّعَامِ ‏"‏ ‏.‏ قَالَ أَصَابَتْهُ السَّمَاءُ يَا رَسُولَ اللَّهِ ‏.‏ قَالَ ‏"‏ أَفَلاَ جَعَلْتَهُ فَوْقَ الطَّعَامِ كَىْ يَرَاهُ النَّاسُ مَنْ غَشَّ فَلَيْسَ مِنِّي ‏"‏ ‏.‏
Reference : Sahih Muslim 102
In-book reference : Book 1, Hadith 190
USC-MSA web (English) reference : Book 1, Hadith 183
  (deprecated numbering scheme)