Verse 3

وَلَقَدْ فَتَنَّا ٱلَّذِينَ مِن قَبْلِهِمْ فَلَيَعْلَمَنَّ ٱللَّهُ ٱلَّذِينَ صَدَقُوا۟ وَلَيَعْلَمَنَّ ٱلْكَـٰذِبِينَ

And indeed We tested those before them, for God must surely know those who are truthful and must surely know the liars.