Chapter 3 talks mostly about doing your duties, what wisdom is, and the importance of action and prayer. These messages were repeated over and over again with examples of the consequences if you do not do these things and the benefits (enlightenment) if you do actively do them. These were the main ideas and each sections touched on them.
My favorite part of chapter 3 was when it said:
"Men say that the senses are strong.
But the mind is stronger than the senses;
the understanding is stronger
than the mind; and strongest is the Self."
It kinda sums up the who section. saying that you need to use your mind to overcome the attachment to sense objects. And that you need to then Understand to move beyond your mind. And above all your Self is your strongest quality. I like how it talks about overcome yourself to be the strongest Self.