You are literally what you think. Your character being a complete sum of your thoughts. Just as plants cannot grow without the seed, actions cannot have been taken without the thought. Through this is the realisation that you hold the key to every situation, and just as gold and diamonds are discovered through much searching and mining, you can discover your own truths and character by digging deep into yourself.
“As a man thinketh in his heart so is he”
Some examples directly from this chapter are: