Surat At-Tawbah - سورة التوبة

عَفَا اللَّهُ عَنكَ لِمَ أَذِنتَ لَهُمْ حَتَّىٰ يَتَبَيَّنَ لَكَ الَّذِينَ صَدَقُوا وَتَعْلَمَ الْكَاذِبِينَ

Muhsin Khan: May Allah forgive you (O Muhammad SAW). Why did you grant them leave (for remaining behind, you should have persisted as regards your order to them to proceed on Jihad), until those who told the truth were seen by you in a clear light, and you had known the liars?