The mind-blowing part of this entire story, though, isn’t that only one leper came back to “give thanks,” but that the Lord Jesus healed all ten knowing full well that only one would come back.
Faith should later again flow forth from our heart’s depths to our neighbor freely and unhindered in good works; not that we wish to rest our salvation in them; for God will not have that, but wishes the conscience to rest in himself alone.
There are plenty of reasons why you do not already do whatever you want out of fear of the law, and you will find these reasons persist and remain long after the gospel has its way with you.