Surat An-Nahl (91-92)

{وَأَوْفُواْ بِعَهْدِ اللّهِ إِذَا عَاهَدتُّمْ وَلاَ تَنقُضُواْ الأَيْمَانَ بَعْدَ تَوْكِيدِهَا وَقَدْ جَعَلْتُمُ اللّهَ عَلَيْكُمْ كَفِيلاً إِنَّ اللّهَ يَعْلَمُ مَا تَفْعَلُونَ} (النحل: 91 )

91- Stick to your covenants with Allah and keep to your promises as He commanded you, and do not break them after you had made Allah a witness over you; verily Allah knows everything and shall reward or punish you for your actions.

{وَلاَ تَكُونُواْ كَالَّتِي نَقَضَتْ غَزْلَهَا مِن بَعْدِ قُوَّةٍ أَنكَاثاً تَتَّخِذُونَ أَيْمَانَكُمْ دَخَلاً بَيْنَكُمْ أَن تَكُونَ أُمَّةٌ هِيَ أَرْبَى مِنْ أُمَّةٍ إِنَّمَا يَبْلُوكُمُ اللّهُ بِهِ وَلَيُبَيِّنَنَّ لَكُمْ يَوْمَ الْقِيَامَةِ مَا كُنتُمْ فِيهِ تَخْتَلِفُونَ} (النحل: 92 )

92- O people do not be like that woman who sews a garment then untie it after it is nearly finished. This is an example for those who break their promises after you have confirmed them. So, you break your promises easily which is a treason, and you say that Muhammad and those people who believed with him are only few and weak and Quraysh is more powerful and more in number. This is only an affliction from Allah to see your determination and truthfulness, and test your loyalty. On the Day of Resurrection, Allah shall separate between people in things which they used to differ about in the world and show the truth to them.