Common question answered - if God loves us, why would he punish a sinner? (sometimes people state this as a disbelief that he would)

Oftentimes Alma's teaching to Corianton is considered a big discourse on not sinning (particularly around adultery), which it is, but in the process, Alma answers some interesting questions. The question in Alma 42 for instance is this, 

 1 And now, my son, I perceive there is somewhat more which doth worry your mind, which ye cannot understand—which is concerning the ^ajustice of God in the ^bpunishment of the sinner; for ye do try to suppose that it is ^cinjustice that the sinner should be consigned to a state of misery.

Or in other words, "doesn't God love all his children. If so, would he really punish them for "sinning"? 

That's a common question. Very common. Especially if you include those who believe that grace covers for all sins with limited or no effort on the part of the sinner. Alma does his best to answer. I find his example particularly powerful:

He answers with a lot of strong doctrinal ideas, even going back to the Fall and explaining the role the Fall has in the answer; this seems to be the epitome of persuading with, "pure knowledge" as is talked about in D.C. 121. It's an example of the power that can come from having a lot of knowledge about how the world actually works. 

As I think about persuasion and the right way to do it, I believe the example of pure knowledge is a common one that's trying to be taught. When the prophets give discourses, they're trying to teach truth in a powerful way that convinces people to act differently. It may be the persuasion "tactic" that is shown the most out of those the Lord talks about in D.C. 121: 

 41 No ^apower or influence can or ought to be maintained by virtue of the ^bpriesthood, only by ^cpersuasion, by ^dlong-suffering, by gentleness and meekness, and by love unfeigned;

 42 By ^akindness, and pure ^bknowledge, which shall greatly enlarge the ^csoul without ^dhypocrisy, and without ^eguile—

I think it might be worth going through chapters and examples and think about the way that the prophet's persuaded and which of these methods are being shown as examples.