The followings are translations of book entitled “The Principle of Happiness”
“The Fourfold Path to True Happiness
I would like to address the main theme of this lecture, the principles of happiness, which are unique to Happy Science. THere are numerous way to become happy, but the kind of happiness I am talking about is not the sort you can enjoy only in this world. It is a joy that carries over from this world to the next. We’re exploring principles of happiness that apply to the past, the present, and the future. The starting point of these principles is willingness to explore Right Mind. Every individual has a diamond within, and this pure diamond represents Right Mind. You may think that highly developed spirits are better than lower-level spirits, for example, that Tathagatas of the eighth dimension are greater than Bodhisattva of the seventh, and Bodhisattva are better than the spirits in the Light Realm of the sixth dimension in the other world.
However, people should not be judged by their spiritual level alone. The diamond within everyone is essentially the same, the only difference being in the level of refinement and the brilliance of the diamond, which is the result of numerous incarnations. Those who make the effort to polish the diamond within become angels of light. So if you continue to refine your inner diamond, it will surely shine. This is true for everyone.
However, no one can become a Tathagata instantly. To make your diamond shine brightly, you must put forth constant and tireless efforts. These efforts are exactly the same as the exploration of Right Mind; this is the spiritual discipline that allows you to discover your true nature. Through daily effort to explore Right Mind, you will enter the next stage, in which you seek true happiness.”