The Prophet ﷺ said, "Whoever takes the property of a Muslim by taking a false oath, will meet Allah Who will be angry with him." Then the Prophet ﷺ recited the Verse:-- 'Verily those who purchase a small gain at the cost of Allah's Covenant and their oaths, they shall have no portion in the Hereafter, neither will Allah speak to them, nor look at them.' (3.77)  

قَالَ رَسُولُ اللَّهِ ﷺ مَنِ اقْتَطَعَ مَالَ امْرِئٍ مُسْلِمٍ بِيَمِينٍ كَاذِبَةٍ لَقِيَ اللَّهَ وَهْوَ عَلَيْهِ غَضْبَانُ قَالَ عَبْدُ اللَّهِ ثُمَّ قَرَأَ رَسُولُ اللَّهِ ﷺ مِصْدَاقَهُ مِنْ كِتَابِ اللَّهِ جَلَّ ذِكْرُهُ {إِنَّ الَّذِينَ يَشْتَرُونَ بِعَهْدِ اللَّهِ وَأَيْمَانِهِمْ ثَمَنًا قَلِيلاً أُولَئِكَ لاَ خَلاَقَ لَهُمْ فِي الآخِرَةِ وَلاَ يُكَلِّمُهُمُ اللَّهُ} الآيَةَ  

He who appropriated the right of a Muslim by (swearing a false) oath, Allah would make Hell-fire necessary for him and would declare Paradise forbidden for him. A person said to him: Messenger of Allah, even if it is something insignificant? He (the Holy Prophet) replied: (Yes) even if it is the twig of the arak tree.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنِ اقْتَطَعَ حَقَّ امْرِئٍ مُسْلِمٍ بِيَمِينِهِ فَقَدْ أَوْجَبَ اللَّهُ لَهُ النَّارَ وَحَرَّمَ عَلَيْهِ الْجَنَّةَ فَقَالَ لَهُ رَجُلٌ وَإِنْ كَانَ شَيْئًا يَسِيرًا يَا رَسُولَ اللَّهِ قَالَ وَإِنْ قَضِيبًا مِنْ أَرَاكٍ  

A bedouin came to the Prophet ﷺ and said, "O Messenger of Allah ﷺ! What are the biggest sins?: The Prophet ﷺ said, "To join others in worship with Allah." The bedouin said, "What is next?" The Prophet ﷺ said, "To be undutiful to one's parents." The bedouin said "What is next?" The Prophet ﷺ said "To take an oath 'Al-Ghamus." The bedouin said, "What is an oath 'Al-Ghamus'?" The Prophet ﷺ said, "The false oath through which one deprives a Muslim of his property (unjustly).  

جَاءَ أَعْرَابِيٌّ إِلَى النَّبِيِّ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ مَا الْكَبَائِرُ قَالَ الإِشْرَاكُ بِاللَّهِ قَالَ ثُمَّ مَاذَا قَالَ ثُمَّ عُقُوقُ الْوَالِدَيْنِ قَالَ ثُمَّ مَاذَا قَالَ الْيَمِينُ الْغَمُوسُ قُلْتُ وَمَا الْيَمِينُ الْغَمُوسُ قَالَ الَّذِي يَقْتَطِعُ مَالَ امْرِئٍ مُسْلِمٍ هُوَ فِيهَا كَاذِبٌ