Happy: You obviously did not learn nach in yeshiva! How many king’s can you count that enforced the torah? I can only name 2-3, can you name more? I would like to know!
Throughout Jewish history, the kings used his army to fight civil wars (that means killing other Jews), kill talmida chocomim, kill Bnai Yisroel who wanted to be Orla Regel!, the armys killed out almost ALL of Beni Dovid on the orders of Queen Athalyah. For your sake, I hope this was NOT a Jewish army, but mercenaries because how could the sanhedrin who were the top commanders have allowed this!!!!???? Please go learn some Nach and you may be shocked that our history was bloody and cruel!
Dovid Hamelech’s army was comprised of outcasts, see Shmuel 1, perek 22, which clearly states that his initial army, and later the core of his regular army were outcasts. Yes, there may be 1 or 2 famous people, but the majority were not!
Yes, you can bring the medrish of Ben Sora Imorah, or that it never happened etc…but the HALACHA still remains!
How would you classify the current IDF? Milchemes Mitzvah or Rehus, or Cheyuv? Based on the Ramban it would be a mitzvah and according to the Mishna in Sotah, there are not exemptions (there is a machlokes) and even WOMEN must go fight or help!
So again, please show me ONE instance throughout the torah where the King says do A, and then Sanhedrin says do B, the army listened to the Sanhedrin???!!!! All I need is ONE instance! Until then, I will stand by my premise that a Jewish Army was there for the King to order them to enforce the torah (if he felt like it) or kill other jews! They were not there to enforce the torah, but to enforce the Kings word.
If Dovid or Saul wanted them to enforce the torah, like Yehoshaya, then they did, but that was not their job!