Devotional service, why it achieves the four goals of life

Essentially all beings are engaged somewhere along the chain of service to Krishna. At the bottom of this chain is kama or sensory gratification, those that are pursueing this goal acheive only kama, kama is essentially all the enjoyments that are avaliable in life, and these enjoyments are essential for healthy happy being. Tantra is the associated yoga with this goal but if it is yoga it is divine. Next comes economic development, those that acheive this goal also acheive that of sensory gratification. Economic development involves moving society forward with developments and basically providing economic stabilty to provide for sensory gratification and move one forwards in life. Next is religiosity, this involves some form of religious engagement and achieves the previous two goals as well. Liberation is the fourth goal, and this is basically freedom from suffering and bondage in this material world and achieves the previous three goals. Devotional Service is the fifth and final goal of life, transcending and including all previous goals it acheives the results of kama, artha, dharma, and moksha whilst pursuing and achieving the goal of transcendental loving service to the Supreme Personality of Godhead.