Hadith 513480
Chapter 31: Business Transactions - كتاب البيوع
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يُونُسَ بْنِ يُوسُفَ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، مَرَّ بِحَاطِبِ بْنِ أَبِي بَلْتَعَةَ وَهُوَ يَبِيعُ زَبِيبًا لَهُ بِالسُّوقِ فَقَالَ لَهُ عُمَرُ بْنُ الْخَطَّابِ إِمَّا أَنْ تَزِيدَ فِي السِّعْرِ وَإِمَّا أَنْ تُرْفَعَ مِنْ سُوقِنَا .
Yahya related to me from Malik from Yunus ibn Yusuf from Said ibn al-Musayyab that Umar ibn al-Khattab passed by Hatab ibn Abi Baltaa who was underselling some of his raisins in the market. Umar ibn al- Khattab said to him, "Either increase the price or leave our market."
Reference Muwatta Malik 513480
USC-MSA web (English) reference : Book 31, Hadith 57