I heard the Messenger of Allah ﷺ say, "Swearing oaths makes merchandise sell quickly but wipes away the blessing."
سمعت رسول الله ﷺ يقول: الحلف منفقة للسلعة ممحقة للبركة.
Bukhari narrated it in the Book of Sales (2087), and Muslim in the Book of Sharecropping (1606), by way of Yunus, from Ibn Shihab, from Ibn Musayab, that Abu Hurairah said, and he mentioned it. The wording given is Bukhari's. Muslim's wording has "effacing of profit."His saying "munfiqah" is with a fatha on the meem and the fa, with a silent noon between them, a mafalah form from "nifaq" (with a fatha on the noon), meaning brisk sale, the opposite of stagnation.