Al-An'am - 6:53

وَكَذَلِكَ فَتَنَّا بَعْضَهُم بِبَعْضٍ لِّيَقُولواْ أَهَـؤُلاء مَنَّ اللّهُ عَلَيْهِم مِّن بَيْنِنَا أَلَيْسَ اللّهُ بِأَعْلَمَ بِالشَّاكِرِينَ
[6:53]
And thus do We try some of them by others so that they say: Are these they upon whom Allah has conferred benefit from among us? Does not Allah best know the grateful?
Thus did We try some of them by comparison with others, that they should say: "Is it these then that Allah hath favoured from amongst us?" Doth not Allah know best those who are grateful?
And even so do We try some of them by others, that they say: Are these they whom Allah favoureth among us? Is not Allah best Aware of the thanksgivers?