"Beware of taking oaths a great deal when selling, for it may help you to make a sale but it destroys the blessing." (Using translation from Nasāʾī 4460)
سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ إِيَّاكُمْ وَكَثْرَةَ الْحَلِفِ فِي الْبَيْعِ؛ فَإِنَّهُ يُنَفِّقُ ثُمَّ يَمْحَقُ