Surah At-Taubah Verse 122 - English Translation by Muhammad Asad
Surah At-Taubah۞وَمَا كَانَ ٱلۡمُؤۡمِنُونَ لِيَنفِرُواْ كَآفَّةٗۚ فَلَوۡلَا نَفَرَ مِن كُلِّ فِرۡقَةٖ مِّنۡهُمۡ طَآئِفَةٞ لِّيَتَفَقَّهُواْ فِي ٱلدِّينِ وَلِيُنذِرُواْ قَوۡمَهُمۡ إِذَا رَجَعُوٓاْ إِلَيۡهِمۡ لَعَلَّهُمۡ يَحۡذَرُونَ
With all this, it is not desirable that all of the believers take the field [in time of war]. From within every group in their midst, some shall refrain from going forth to war, and shall devote themselves [instead] to acquiring a deeper knowledge of the Faith. and [thus be able to] teach their home-coming brethren, so that these [too] might guard themselves against evil