رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 1720
The Book of the Prohibited actions
Abomination of Swearing in Transaction
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ يَقُولُ: الْحَلِفُ مُنَفِّقَةٌ لِلسِّلْعَةِ، مُمْحِقَةٌ للكسب ((مُتَّفَقٌ عَلَيْهِ)).
Abu Hurairah (May Allah be pleased with him) said: I heard the Messenger of Allah (ﷺ) saying, "Swearing produces a ready sale for a commodity, but blots out the blessing." [Al-Bukhari and Muslim].
Riyad as-Salihin, 1720