That the Messenger of Allah ﷺ said: "Whoever takes a false oath to deprive a Muslim of his wealth, he will meet Allah while He is angry with him." Al-Ash'ath bin Qais said: "It is about me, by Allah! There was a dispute about some land between myself and a man from the Jews who denied my ownership of it, so I took him to the Prophet ﷺ. The Messenger of Allah ﷺ said to me: 'Do you have any proof ?' I said: 'No'. So he said to Jew: 'Take an oath.' I said: 'O Messenger of Allah! If he takes an oath then my property will be gone!' So Allah, Most High revealed: Verily those who purchase a small gain at the cost of Allah's Covenant and their oaths.. until the end of the Ayah."
قَالَ رَسُولُ اللَّهِ ﷺ مَنْ حَلَفَ عَلَى يَمِينٍ وَهُوَ فِيهَا فَاجِرٌ لِيَقْتَطِعَ بِهَا مَالَ امْرِئٍ مُسْلِمٍ لَقِيَ اللَّهَ وَهُوَ عَلَيْهِ غَضْبَانُ فَقَالَ الأَشْعَثُ بْنُ قَيْسٍ فِيَّ وَاللَّهِ لَقَدْ كَانَ ذَلِكَ كَانَ بَيْنِي وَبَيْنَ رَجُلٍ مِنَ الْيَهُودِ أَرْضٌ فَجَحَدَنِي فَقَدَّمْتُهُ إِلَى النَّبِيِّ ﷺ فَقَالَ لِي رَسُولُ اللَّهِ ﷺ أَلَكَ بَيِّنَةٌ قُلْتُ لاَ فَقَالَ لِلْيَهُودِيِّ احْلِفْ فَقُلْتُ يَا رَسُولَ اللَّهِ إِذًا يَحْلِفَ فَيَذْهَبَ بِمَالِي فَأَنْزَلَ اللَّهُ تَعَالَى (إِنَّ الَّذِينَ يَشْتَرُونَ بِعَهْدِ اللَّهِ وَأَيْمَانِهِمْ ثَمَنًا قَلِيلاً ) إِلَى آخِرِ الآيَةِ