This chapter is right after Alma tells the poor Zoramites about the need to be humble and faith being like a seed. The chapter begins with them inquiring about how to plant the seed, or how to exercise their faith. They are particularly concerned because the synagogue is off limits to them, but Alma emphasizes that you can worship God at any time. That seems like such a no-brainer to me, but I guess that when all the rich people were only worshipping on the Sabbath, and in such loud, effusive ways, the idea of quiet, constant faith was probably quite foreign!
Maybe there were some skeptical looks in the congregation, because Adam starts quoting scriptures to prove that you really can worship God at any time. He quotes Zenos, who talks about praying in the wilderness, and at home, in his fields, and in his closet. Also, remember how the Zoramites denied Christ? Alma teaches the poor about Christ and quotes the testimonies of Zenos and another prophet, Zenock. We read about these prophets in other parts of the Book of Mormon, but we know nothing about them. It makes me really curious. Jacob quoted them in the allegory of the olive tree. When do you think they lived? Anyway, their influence was long-lasting, because Alma uses them as examples.
Finally, Alma talks about Moses, and how in the wilderness the people only had to look up at the snake on a pole to be healed. Some people were still too stubborn to do that. Alma tells the people to not be so stiffnecked that they aren't willing to believe in Christ, which is as easy as looking up at a serpent on a pole that is right in front of us. I like verses 21-22:
21 O my brethren, if ye could be healed by merely casting about your eyes that ye might be healed, would ye not behold quickly, or would ye rather harden your hearts in unbelief, and be slothful, that ye would not cast about your eyes, that ye might perish?
22 If so, wo shall come upon you; but if not so, then cast about your eyes and begin to believe in the Son of God, that he will come to redeem his people, and that he shall suffer and die to atone for their sins; and that he shall rise again from the dead, which shall bring to pass the resurrection, that all men shall stand before him, to be judged at the last and judgment day, according to their works.