12:72
قَالُواْ نَفْقِدُ صُوَاعَ الْمَلِكِ وَلِمَن جَاء بِهِ حِمْلُ بَعِيرٍ وَأَنَاْ بِهِ زَعِيمٌ
They said: "We miss the great beaker of the king; for him who produces it, is (the reward of) a camel load; I will be bound by it."
16:91
وَأَوْفُواْ بِعَهْدِ اللّهِ إِذَا عَاهَدتُّمْ وَلاَ تَنقُضُواْ الأَيْمَانَ بَعْدَ تَوْكِيدِهَا وَقَدْ جَعَلْتُمُ اللّهَ عَلَيْكُمْ كَفِيلاً إِنَّ اللّهَ يَعْلَمُ مَا تَفْعَلُونَ
Fulfil the Covenant of Allah when ye have entered into it, and break not your oaths after ye have confirmed them; indeed ye have made Allah your surety; for Allah knoweth all that ye do.