CC Ādi 9.42

etāvaj janma-sāphalyaṁ
dehinām iha dehiṣu
prāṇair arthair dhiyā vācā
śreya-ācaraṇaṁ sadā
Synonyms: 
etāvat — up to this; janma — of birth; sāphalyam — perfection; dehinām — of every living being; iha — in this world; dehiṣu — toward those who are embodied; prāṇaiḥ — by life; arthaiḥ — by wealth; dhiyā — by intelligence; vācā — by words; śreyaḥ — eternal good fortune; ācaraṇam — acting practically; sadā — always.
Translation: 
“ ‘It is the duty of every living being to perform welfare activities for the benefit of others with his life, wealth, intelligence and words.’
Purport: 

There are two kinds of general activities — śreyas, or activities which are ultimately beneficial and auspicious, and preyas, or those which are immediately beneficial and auspicious. For example, children are fond of playing. They do not want to go to school to receive an education, and they think that to play all day and night and enjoy with their friends is the aim of life. Even in the transcendental life of Lord Kṛṣṇa, we find that when He was a child He was very fond of playing with His friends of the same age, the cowherd boys. He would not even go home to take His dinner. Mother Yaśodā would have to come out to induce Him to come home. Thus it is a child’s nature to engage all day and night in playing, not caring even for his health and other important concerns. This is an example of preyas, or immediately beneficial activities. But there are also śreyas, or activities which are ultimately auspicious. According to Vedic civilization, a human being must be God conscious. He should understand what God is, what this material world is, who he is, and what their interrelationships are. This is called śreyas, or ultimately auspicious activity.

In this verse of Śrīmad-Bhāgavatam it is said that one should be interested in śreyas. To achieve the ultimate goal of śreyas, or good fortune, one should engage everything, including his life, wealth and words, not only for himself but for others also. However, unless one is interested in śreyas in his own life, he cannot preach of śreyas for the benefit of others.

This verse cited by Śrī Caitanya Mahāprabhu applies to human beings, not to animals. As indicated in the previous verse by the words manuṣya-janma, these injunctions are for human beings. Unfortunately, human beings, although they have the bodies of men, are becoming less than animals in their behavior. This is the fault of modern education. Modern educators do not know the aim of human life; they are simply concerned with how to develop the economic condition of their countries or of human society. This is also necessary; the Vedic civilization considers all aspects of human life, including dharma (religion), artha (economic development), kāma (sense gratification) and mokṣa (liberation). But humanity’s first concern should be religion. To be religious, one must abide by the orders of God, but unfortunately people in this age have rejected religion, and they are busy in economic development. Therefore they will adopt any means to get money. For economic development one does not need to get money by hook or by crook; one needs only sufficient money to maintain his body and soul. However, because modern economic development is going on with no religious background, people have become lusty, greedy and mad after money. They are simply developing the qualities of rajas (passion) and tamas (ignorance), neglecting the other quality of nature, sattva (goodness), and the brahminical qualifications. Therefore the entire society is in chaos.

The Bhāgavatam says that it is the duty of an advanced human being to act in such a way as to facilitate human society’s attainment of the ultimate goal of life. There is a similar verse in the Viṣṇu Purāṇa, part three, chapter twelve, verse 45, which is next quoted in the Caitanya-caritāmṛta.