Armies of the prophets

[A_Submitter]

Salam,

Throughout Quran we are given examples of armies and war, but one thing that wasn't clear for me is this

Did the armies only consist of believers?
Example Saul's army (this one is more obvious, there were only believers), Solomon's army (the Jinn, did they submit to God alone?), Muhammed's army?

Salam