“And they did preach the word unto many, and few believed on the words which they taught.”
When we think of missionary work in the Book of Mormon, we often think about Ammon and his miraculous success. We also emended Aaron’s later success with King Lamoni’s father. But we forget that Aaron’s first mission was effectively a near total failure. They were first kicked out of Jerusalem by the people and then imprisoned in harsh circumstances. And through all this, they preached to many but few believed.
But their preaching lay a foundation for incredible success later on. Until Lamoni had been converted and started a transition towards religious freedom among them, the people had not been ready yet. But the work done among them was not vain.
It is easy as a missionary or RM to get discouraged and wonder if what you do makes a real difference. In my mission many struggled with baptisms or saw those that join the church quickly fall away.
I think we can learn just as much from the failure of this first mission as the success of subsequent missions.