How to get people to do things

I reread "How to get people to do things" by Robert Conklin. The first time to read it was more than ten years ago. I have been strongly impressed that we could not make people to do something only by logic, rather we needed emotional persuasion. And now, I want to read it again. I don't know why, but I strengthen my mind to be gentle for others, because, "The more we give of anything, the more we shall get back" as written in the Bible. People's reaction to me is decided by my attitude to them, so if we hope that people are gentle to me, we must be gentle for them.
By the way, we are struggling to analyze "Trollkarens Hatt (Finn family Moomintroll)" in Moomin class. In this story, a wizard appears. He have searched the King of ruby all over the world for more than four hundreds years. At last he found it in Moomin valley, but it have been already owned by other people. He begged them for it, but they denied. Then he began to grant the Moomin valley's hopes by his magic. At last, the King of ruby's owners wish the Queen of ruby and give it for the wizard. He can use his magic for other people's hopes but cannot it by himself.
This story also tells "The more we give of anything, the more we shall get back". I wander my students can be aware of the message?