Submission is a word that we usually find demeaning. We don’t think of someone submitting as being a positive thing. A wrestler who submits, loses. If you submit to a bully you’re considered a wimp. A wife submitting sounds like she’s being taking advantage of or abused. A team that submits has given up. It’s not positive sounding at all, nor was it in Paul’s day.
When Paul talked about submitting I can see the people scratching their heads, wondering why anyone would want to submit to another. They had armies who went into battle. If their army submitted then they had lost the battle. That’s no good.