وَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَا تَسْتَقْبِلُوا وَلَا تُحَفِّلُوا وَلَا يَنْعِقْ بَعْضُكُمْ لِبَعْضٍ
مسند امام احمد بن حنبل · Hadith 2313
The Messenger of Allah (PBUH) said: "Do not go out to meet incoming traders, do not leave the milk of a she-camel or sheep to accumulate [in its udder, so as to deceive a prospective buyer], do not try to sell by artificial means."
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020