Narrated by:`Abdullah ibn `Umar
Narrated `Abdullah ibn `Umar:Allah's Messenger (ﷺ) said, "He who buys foodstuff should not sell it till he is satisfied with the measure with which he has bought it.
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنِ ابْتَاعَ طَعَامًا فَلاَ يَبِيعُهُ حَتَّى يَسْتَوْفِيَهُ ".
Bukhari
Sales and Trade • Hadith 78