وَلَقَدْ فَتَنَّا الَّذِيْنَ مِنْ قَبْلِهِمْ فَلَيَعْلَمَنَّ اللّٰهُ الَّذِيْنَ صَدَقُوْا وَلَيَعْلَمَنَّ الْكٰذِبِيْنَ ( العنكبوت: ٣ )
Wa laqad fatannal lazeena min qablihim fala ya'lamannal laahul lazeena sadaqoo wa la ya'lamannal kaazibeen (al-ʿAnkabūt 29:3)
But We have certainly tried those before them, and Allah will surely make evident those who are truthful, and He will surely make evident the liars. (Al-'Ankabut  : 3)
1 Mufti Taqi Usmani
Indeed We have tested those who were before them. So Allah will surely know the ones who are truthful, and He will surely know the liars.