عَنْ عَبْدِ اللَّهِ بْنِ أُنَيْسٍ الْجُهَنِيِّ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِنَّ مِنْ أَكْبَرِ الْكَبَائِرِ الشِّرْكُ بِاللَّهِ وَعُقُوقُ الْوَالِدَيْنِ وَالْيَمِينُ الْغَمُوسُ وَمَا حَلَفَ حَالِفٌ بِاللَّهِ يَمِينًا صَبْرًا فَأَدْخَلَ فِيهَا مِثْلَ جَنَاحِ بَعُوضَةٍ إِلَّا جَعَلَهُ اللَّهُ نُكْتَةً فِي قَلْبِهِ إِلَى يَوْمِ الْقِيَامَةِ
It is narrated from Sayyiduna Abdullah bin Anis Juhani, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: Associating partners with Allah, disobedience to parents, and false oaths are among the gravest sins. Whoever swears a false oath in the name of Allah and introduces even as much falsehood as the wing of a mosquito into it, Allah Almighty will mark that evil as a spot upon his heart until the Day of Resurrection.