Just as rust, which arose from the iron itself, wears out the iron, likewise, performing an action without examination would destroy us by projecting us into a negative state of existence.
So the first step in seeking happiness is learning. We first have to learn how negative emotions and behaviors are harmful to us and how positive emotions are helpful.
If you have a great deal of knowledge, but you're governed by negative emotions, then you tend to use your knowledge in negative ways. Therefore, while you are learning, don't forget the importance of warmheartedness.