As the OP states why would Israel /Jewish nation need to have an army at all ? If they were the chosen people as the bible states under a theocracy , why would the men of Israel need an army .? to protect them ?
Couldnt Jehovah do so ?
The bible shows in many passages God coming to the aid of the Israelites , my question is why wasnt he their all the time ? to defend them ?
The argument that he only defended them when they were faithful as a nation , doesnt hold any water. why ? because when they were faithful he didnt defend them , they still had to rely on their armies to do battle with their enemies with his so called blessing.
So under the theocracy of Jehovahs Rule in the Old Testament when the Israelites were in his favour , the army of the jewish nation engaged in warfare with their enemies , which meant jews killing men women and children by piercing them with a sword at jehovahs command.
Can you imagine yourself participating in such an action today ? Killing a man won or child ? obeying Jehovah ?
Jehovah is God Almighty right ? he has shown that he can kill 185000 in one night , by his Angels ,so why would he need to have his chosen people , human beings involved in putting to death by the sword thousands of people over many centuries ?
As an Almighty God Jehovah he didnt need to involve his chosen people the Israelites in any bloodshed at all , he could have done it like he has done many times before , the fact that he did involve his subjects in this bloodshed raises some serious questions ?
What do you think tose questions could be ?