If you'll remember, there was a young priest among the priests of King Noah who believed Abinidi and started writing down what he was saying. Which didn't go over super well with the priests of the king, so Alma had to go into hiding and started teaching the people the things that Abinadi said, about getting to live after we die, and redemption and the Atonement. His faith was so strong, he talked about these things like they had already happened; time was collapsed for him.

He taught everyone who would listen to him, but secretly, because this is the kind of thing that would really make the king mad. He taught with power, and lots of people believed him, and they all went down to a place called Mormon, where Alma had been hiding from Noah.

After a few days, there were a lot of people hiding in this thicket listening to Alma talk. And he said, "Look, there's some water right there—if you are ready to carry your brothers and sisters who can't carry themselves and to be carried in your turn, to feel with each other, to laugh and to cry and suffer and rejoice with each other, to testify of God and stand as his witness, even when that's terribly uncomfortable and inconvenient, even when that means that they'll burn you like they burned Abinidai, if you want to do these things so that you can be God's people and children, so that you can be part of his work and become like him--if this is what you want, then in the name of God let's go be baptized. Let's witness to him that we're willing to make him promises and try really hard to keep them, even when we know and he knows that we can't really do that well right now, so that he can send his spirit to us to make us better than we are."