Al-Ankabut - 29:3

وَلَقَدْ فَتَنَّا الَّذِينَ مِن قَبْلِهِمْ فَلَيَعْلَمَنَّ اللَّهُ الَّذِينَ صَدَقُوا وَلَيَعْلَمَنَّ الْكَاذِبِينَ
[29:3]
And certainly We tried those before them, so Allah will certainly know those who are true and He will certainly know the liars.
We did test those before them, and Allah will certainly know those who are true from those who are false.
Lo! We tested those who were before you. Thus Allah knoweth those who are sincere, and knoweth those who feign.