faith is not doing it is trusting, we do because we trust, if we do not do, it is because we lack trust
using your example, when the commander told me to do something, and I did it and It worked, my faith grew, he was the author of he way, I trusted him, and he worked on finishing my faith by keeping putting me in places I will succeed,
the more he tells me to do and the more he is proven trustworthy, the more I do, and the harder I work, because my faith grows more and more,
if he told me to do something that did not work, my faith fell, I would not work so hard, if he kept failing, I would lose failth altogether,
Lets take this to God,
God said if I trust him, he will wash me, make me clean, change my life, give me hope, make me a new creature, give me rest and peace, and show me the way to lead a life which is blessed,
he is the author and finisher, because it is all based on his promises,he authored the way to these hinge, and he way to make sure these things come true
once i am saved, t he more things I do which seems odd to me before, and realize. My way is not Gods way, yet I was blessed by doing, my faith grows, the more I trust him, the more my faith grows,
in contrast, the times I decide I can handle it, and it fails. Or I am not blessed by doing it, Well then I realize how untrustworthy I am and how much more I need to trust God,
thats why may faith grows, because whenever I do it Gods way, it works, whenever I do it my way, I fall on my face,
now, I want to give that all up, and live a life of falling on my face? Why do you think the prodigal son returned. He knew his father was trustworthy and could take care of him,
fr usm we may forget how before we were saved we failed, no matter what we did, we could not find happiness, and when we tried to do it again, hwe failed again.
A person who can go go back to the world in unbelief in my view, never experienced gods faithfulness, you can not in my view experience that, then think you are better off on your own the old way, it won't happen (not to mentions, just like the commands will punish you your not following him, so will god, if your really his son or daughter)