Happiness is the greatest thing one can attain in this world, in this world and the next world. Yama said that if the goal is profound satisfaction, deepest the highest possible happiness then we need to develop a scale of happiness. The economics would be very interested. There the uppanishad, this is the titerio-panishad. And there what it says is briefly I will outline it,. It will give you a background to what we are going, what Yama is going to indicate now.
Swami Sarvapriyananda teaches the Katha Upanishad, which is one of India's most revered texts and a part of the Vedas. It is a collection of philosophical poems representing a conversation between the sage Naciketas and Yama (god of death). They discuss the nature of Atman, Brahman and Moksha(liberation).