Jami` at-Tirmidhi, Book 14, Hadith 108 (In-Book) ⓘ

Narrated Suwaid bin Qais: "Makhrafah Al-'Abdi and I brought linens from Hajar. The Prophet came to us in bargain with us with some pants. There was someone with me who weighed (the goods) to determine the value. So the the Prophet said to the one weighing: 'Weigh and add more.'" [He said:] There are narrations on this topic from Jabir and Abu Hurairah. [Abu 'Eisa said:] The Hadith of Suwaid is a Hasan Sahih Hadith. The people of knowledge consider it recommended to add more when weighing. Shu'bah reported this Hadith from Simak, so he said: "From Abu Safwan" and he mentioned the narration.

حَدَّثَنَا هَنَّادٌ، وَمَحْمُودُ بْنُ غَيْلاَنَ، قَالاَ حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ سِمَاكِ بْنِ حَرْبٍ، عَنْ سُوَيْدِ بْنِ قَيْسٍ، قَالَ جَلَبْتُ أَنَا وَمَخْرَفَةُ الْعَبْدِيُّ، بَزًّا مِنْ هَجَرَ فَجَاءَنَا النَّبِيُّ صلى الله عليه وسلم فَسَاوَمَنَا بِسَرَاوِيلَ وَعِنْدِي وَزَّانٌ يَزِنُ بِالأَجْرِ فَقَالَ النَّبِيُّ صلى الله عليه وسلم لِلْوَزَّانِ ‏ "‏ زِنْ وَأَرْجِحْ ‏" ‏ ‏.‏ قَالَ وَفِي الْبَابِ عَنْ جَابِرٍ وَأَبِي هُرَيْرَةَ ‏.‏ قَالَ أَبُو عِيسَى حَدِيثُ سُوَيْدٍ حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏ وَأَهْلُ الْعِلْمِ يَسْتَحِبُّونَ الرُّجْحَانَ فِي الْوَزْنِ ‏.‏ وَرَوَى شُعْبَةُ هَذَا الْحَدِيثَ عَنْ سِمَاكٍ فَقَالَ عَنْ أَبِي صَفْوَانَ وَذَكَرَ الْحَدِيثَ ‏.‏