9:122
۞ وَمَا كَانَ ٱلْمُؤْمِنُونَ لِيَنفِرُوا۟ كَآفَّةً ۚ فَلَوْلَا نَفَرَ مِن كُلِّ فِرْقَةٍ مِّنْهُمْ طَآئِفَةٌ لِّيَتَفَقَّهُوا۟ فِى ٱلدِّينِ وَلِيُنذِرُوا۟ قَوْمَهُمْ إِذَا رَجَعُوٓا۟ إِلَيْهِمْ لَعَلَّهُمْ يَحْذَرُونَ
9:122
Yet it is not for the faithful to go forth en masse. But why should not there a group from each of their sections go forth to become learned in religion, and to warn their people when they return to them, so that they may beware? - Ali Quli Qarai (English)