عَفَا اللَّهُ عَنكَ لِمَ أَذِنتَ لَهُم حَتّىٰ يَتَبَيَّنَ لَكَ الَّذينَ صَدَقوا وَتَعلَمَ الكاذِبينَ

May Allah pardon you, [O Muhammad]; why did you give them permission [to remain behind]? [You should not have] until it was evident to you who were truthful and you knew [who were] the liars.