Three lessons in one post seems audacious, perhaps even doomed to failure. Be that as it may, I can dispatch one lesson immediately: Lesson 40 has no assigned reading. Hasta nunca, cuarenta!
Lesson 38 involves four short passages. The first of these is an apocalyptic warning, in the full, Old Testament sense. Section 38 promises that Jesus Christ will come again soon, but also offers a warning. Here is the first, partial and cryptic, iteration of the warning:
And now I show unto you a mystery, a thing which is had in secret chambers, to bring to pass even your destruction in process of time, and ye knew it not; but now I tell it unto you, and ye are blessed, not because of your iniquity, neither your hearts of unbelief; for verily some of you are guilty before me, but I will be merciful unto your weakness. (D&C 38: 13-14)
I am very much in favor of mercy unto our weakness. But what is the mystery in secret chambers? So far, so confusing. The text pauses for a long digression before the secret chambers reappear; the intervening verses remind us in beautiful and Biblical language that God loves and owns the world, and that He cares about and gives ethical rules on behalf of the rich and the poor.