According to this verse, if one develops the mode of ignorance, after his death he is degraded to an animal form of life. From there one has to again elevate himself, by an evolutionary process, to come again to the human form of life. Therefore, those who are actually serious about human life should take to the mode of goodness and in good association transcend the modes and become situated in Kṛṣṇa consciousness. This is the aim of human life. Otherwise, there is no guarantee that the human being will again attain to the human status.
(Bhagavad-Gita----14:15----purport).

We should never desire to increase the depth of material enjoyment. Material enjoyment should be accepted only up to the point of the bare necessities of life and not more or less than that. To accept more material enjoyment means to bind oneself more and more to the miseries of material existence. More wealth, more women and false aristocracy are some of the demands of the materially disposed man because he has no information of the benefit derived from Viṣṇu worship. By Viṣṇu worship one can derive benefit in this life as well as in life after death. Forgetting these principles, foolish people who are after more wealth, more wives and more children worship various demigods. The aim of life is to end the miseries of life and not to increase them.
(Srimad Bhagavatam----1:2:27----purport).

In the Bhagavad-gītā it is said that those who are mahātmās, or those whose minds have been so broadened as to be engaged in the service of Lord Kṛṣṇa, are under the influence of the internal potency, and the effect is that such broadminded living beings are constantly engaged in the service of the Lord without deviation. That should be the aim of life. And that is the verdict of all the Vedic literatures. No one should bother himself with fruitive activities or dry speculation about transcendental knowledge. Everyone should at once engage himself in the transcendental loving service of the Lord.
(Srimad Bhagavatam----1:2:28-29----purport).

The conditioned souls under material bondage are prisoners of matter, and therefore self-realization is the ultimate aim of life. The whole system of āśrama-dharma is a means to detachment. One who fails to assimilate this spirit of detachment is allowed to enter into family life with the same spirit of detachment. Therefore, one who attains detachment may at once adopt the fourth order, namely, renounced, and thus live on charity only, not to accumulate wealth, but just to keep body and soul together for ultimate realization. Household life is for one who is attached, and the vānaprastha and sannyāsa orders of life are for those who are detached from material life. The brahmacārī-āśrama is especially meant for training both the attached and detached.
(Srimad Bhagavatam----1:9:26----purport).

As long as one is blind to inquiring after self-realization, all material activities, however great they may be, are all different kinds of defeat because the aim of human life is not fulfilled by such unwanted and profitless activities. The function of the human body is to attain freedom from material bondage, but as long as one is fully absorbed in material activities, his mind will be overwhelmed in the whirlpool of matter, and thus he will continue to be encaged in material bodies life after life.
(Srimad Bhagavatam----2:9:36----purport).

It is for this reason only that the Lord advises in the Bhagavad-gītā that one give up all so-called religious activities and completely engage in the devotional service of the Lord to become free from all anxieties due to the dangerous life of material existence. To work situated in sad-dharma is the right direction of life. One's aim of life should be to go back home, back to Godhead, and not be subjected to repeated births and deaths in the material world by getting good or bad bodies for temporary existence. Herein lies the intelligence of human life, and one should desire the activities of life in that way.
(Srimad Bhagavatam----2:10:4----purport).

The perfection of human life is attained by following three principles of civilization: protecting the cows, maintaining the brahminical culture and, above all, becoming a pure devotee of the Lord. Without becoming a devotee of the Lord, one cannot perfect one's human life. The perfection of human life is to be elevated to the spiritual world, where there is no birth, no death, no disease and no old age. That is the highest perfectional aim of human life. Without this aim, any amount of material advancement in so-called comforts can only bring the defeat of the human form of life.
(Srimad Bhagavatam----3:3:28----purport).

When a person considers sense gratification the aim of life, he certainly becomes mad after materialistic living and engages in all kinds of sinful activity. He does not know that due to his past misdeeds he has already received a body which, although temporary, is the cause of his misery. Actually the living entity should not have taken on a material body, but he has been awarded the material body for sense gratification. Therefore I think it not befitting an intelligent man to involve himself again in the activities of sense gratification by which he perpetually gets material bodies one after another.
(Srimad Bhagavatam----5:5:4----purport).

When Lord Kṛṣṇa appeared, He purposefully became a cowherd boy and showed personally how to give protection to the cows and calves. Similarly, He showed respect to Sudāmā Vipra, a real brāhmaṇa. From the Lord's personal activities, human society should learn how to give protection specifically to the brāhmaṇas and cows. Then the protection of religious principles, fulfillment of the aim of life and protection of Vedic knowledge can be achieved. Without protection of cows, brahminical culture cannot be maintained; and without brahminical culture, the aim of life cannot be fulfilled. The Lord, therefore, is described as go-brāhmaṇa-hitāya because His incarnation is only for the protection of the cows and brāhmaṇas. Unfortunately, because in Kali-yuga there is no protection of the cows and brahminical culture, everything is in a precarious position. If human society wants to be exalted, the leaders of society must follow the instructions of Bhagavad-gītā and give protection to the cows, the brāhmaṇas and brahminical culture.
(Srimad Bhagavatam----8:24:5----purport).