According to the verdict of all Vedic literature, the Supreme Personality of Godhead, the living entity and the illusory energy (this material world) constitute the subject matter of knowledge. Everyone should try to understand the relationships among them. First of all, one should try to understand the nature of the Supreme Personality of Godhead. From the sastras we understand that the nature of the Supreme Personality of Godhead is the sum total of eternity, bliss and knowledge. As stated in verse 154 (visnu-saktih para prokta), the Supreme Personality of Godhead is the reservoir of all potencies, and His potencies are all spiritual.