Srila Prabhupada explains in a lecture:
“Nobody knows what the ultimate goal of life is. They think that, “We have got this body, and let us enjoy the senses to the fullest extent. That is the highest perfection of life.” Get some material education – technologist, or something else, material education – get some good post, get good salary, and eat nicely, drink nicely, and enjoy your senses. This is perfection of life. This is going on all over the world. But that is not the goal of life. Therefore, because that is not the goal of life, and we know that this is goal of life, therefore we require the enlightenment from a bona fide spiritual master. Tad vijnanartham sa gurum evabhigacchet samit-panih srotriyam [MU 1.2.12]. That is the Vedic instruction. In order to learn that transcendental science, you must approach a bona fide spiritual master.”
Srila Krishnadasa Kaviraja Gosvami’s Appearance Day— Vrindavana, October 19, 1972
The human form of life is especially meant for making progress in spiritual life. This is the verdict of the revealed scriptures. It is said by Prahlada Maharaja in Srimad Bhagavatam 7.6.1:
Prahlada Maharaja said: “One who is sufficiently intelligent should use the human form of body from the very beginning of life—in other words, from the tender age of childhood—to practice the activities of devotional service, giving up all other engagements. The human body is most rarely achieved, and although temporary like other bodies, it is meaningful because in human life one can perform devotional service. Even a slight amount of sincere devotional service can give one complete perfection.”
Srila Prabhupada explains in a lecture as follows:
“The injunction in the Bhagavad–gita is that tad viddhi, try to understand. Not try, but must try. The human life is meant for understanding tattva, the Absolute Truth. That is the special advantage of the human life. If a human being does not inquire or he’s not trained up to inquire about it, it is a great disadvantage and it is enviousness. In the human life, the chance is there to make a solution of the whole problem, struggle for existence, survival of the fittest. This is going on life after life. Now here is a chance, human life, he can understand what is the goal of life and how to achieve it. He can be trained up. So if that opportunity is refused to the human society by the guardians, by the government, it is a great mis-service, a great disadvantage. To keep them in darkness of animal propensities… Because we are changing our body, here is a chance, after many evolutionary processes, many thousands and millions of years. We are going to the park. How many plants and creepers are there, how many animals, how many aquatics? We have to come through all these processes, evolutionary process. So here is a chance. Therefore for the human being it is advised that try to understand the goal of your life. Tad vijnanartham sa gurum evabhigacchet samit-panih srotriyam [MU 1.2.12]. That is Vedic instruction. Must try. So from the very beginning, if children are not trained up to inquire about the goal of life, they are kept in darkness, simply eat, drink, be merry and enjoy, that is not civilization. They must be trained up. The opportunity must be given so that he can inquire more and more about the goal of life.”
Sri Caitanya-charitamrita, Madhya-lila 20.103 —Washington, D.C., July 8, 1976
Since we are part and parcels of the Lord, it is natural for all living beings to render loving devotional service to the Lord. For example, it is natural for all the limbs of the body to cooperate and work for the pleasure of the stomach.
It is explained in Srimad Bhagavatam 4.31.14
As pouring water on the root of a tree energizes the trunk, branches, twigs and everything else, and as supplying food to the stomach enlivens the senses and limbs of the body, simply worshiping the Supreme Personality of Godhead through devotional service automatically satisfies the demigods, who are parts of that Supreme Personality.
Hence for rendering devotional service to the Lord, every one must cooperate with each other. This must be the goal of one’s family, nation and the entire human society at large.
In Srimad Bhagavatam 7.7.55 it is explained:
“In this material world, to render service to the lotus feet of Govinda, the cause of all causes, and to see Him everywhere, is the only goal of life. This much alone is the ultimate goal of human life, as explained by all the revealed scriptures.”