it is not advisable for the believers to march out altogether. of every division that marches out let a group remain behind to gain understanding of the religion and to notify their people when they have returned to them that they may beware.
وما كان المؤمنون لينفروا كافة فلولا نفر من كل فرقة منهم طائفة ليتفقهوا في الدين ولينذروا قومهم إذا رجعوا إليهم لعلهم يحذرون