Abu Bakr's strategy was to give his generals their mission, the geographical area in which that mission would be carried out, and resources for that purpose. He would then leave it to his generals to accomplish their missions in whatever manner they chose. On the other hand, Umar, in the latter part of his Caliphate, adopted a more hands-on approach, directing his generals where to stay and when to move to the next target and who was to command the left and right-wing of the army in each particular battle. This made conquests comparatively slower but made the campaigns well-organized. Uthman and Ali reverted to Abu Bakr's method, giving missions to their generals and leaving the details to them.
