Sunan an-Nasa'i, Hadith 4597 ⓘ
It was narrated that Ibn 'Abbas said: "The Messenger of Allah said: 'Whoever buys food, let him not sell it until he has checked its weight.""
أَخْبَرَنَا أَحْمَدُ بْنُ حَرْبٍ، قَالَ حَدَّثَنَا قَاسِمٌ، عَنْ سُفْيَانَ، عَنِ ابْنِ طَاوُسٍ، عَنْ أَبِيهِ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنِ ابْتَاعَ طَعَامًا فَلاَ يَبِيعُهُ حَتَّى يَكْتَالَهُ " .
also referenced under: Book 44, Hadith 149 (In-Book) & Volume 5, Book 44, Hadith 4601 (DarusSalam)