The LORD used ML mightily to cause the great truth of salvation by grace through faith alone, as well as other great truths to be brought forth, as well as to come up against many false Catholic doctrines.
ML had been a Catholic priest and wasn’t astute enough to pull away from all of their false doctrines. The Lutheran Church to this day still has a Catholic flavor. I was brought up Lutheran, left Lutheranism becoming an atheist, then later, after I was born again, I knew not to go back to the Lutheran Church.
Slight correction:
Satan used ML mightily to lead souls into damnation by his "faith alone" nonsense.