Therefore, from the very beginning of one's life one should practice bhakti-yoga, which increases one's attachment for Kṛṣṇa. If one daily sees the Deity in the temple, makes offerings by worshiping the Deity, chants the holy name of the Personality of Godhead, and preaches about the glorious activities of the Lord as much as possible, he thus becomes attached to Kṛṣṇa. This attachment is called āsakti. When one's mind is attached to Kṛṣṇa (mayy āsakta-manāḥ), one can fulfill the mission of life in one human birth. If one misses this opportunity, one does not know where he is going, how long he will remain in the cycle of birth and death, and when he will again achieve the human form of life and the chance to return home, back to Godhead. The most intelligent person, therefore, uses every moment of his life to render loving service to the Lord.
(Srimad Bhagavatam----9:9:42----purport).

The example given here is that water is a very nice place for a fish, but the fish is never free from anxiety about death, since big fish are always eager to eat the small fish. phalgūni tatra mahatām: all living entities are eaten by bigger living entities. This is the way of material nature.
ahastāni sahastānām
apadāni catuṣ-padām
phalgūni tatra mahatāṁ
jīvo jīvasya jīvanam
"Those who are devoid of hands are prey for those who have hands; those devoid of legs are prey for the four-legged. The weak are the subsistence of the strong, and the general rule holds that one living being is food for another." (S.B.1:13:47) The Supreme Personality of Godhead has created the material world in such a way that one living entity is food for another. Thus there is a struggle for existence, but although we speak of survival of the fittest, no one can escape death without becoming a devotee of the Lord. Hariṁ vinā naiva sṛtiṁ taranti: one cannot escape the cycle of birth and death without becoming a devotee. This is also confirmed in Bhagavad-gītā (9.3). Aprāpya māṁ nivartante mṛtyu-saṁsāra-vartmani. One who does not attain shelter at the lotus feet of Kṛṣṇa must certainly wander up and down within the cycle of birth and death.
(Srimad Bhagavatam----9:13:10----purport).

Śrīla Narottama dāsa Ṭhākura says:
manuṣya-janama pāiyā, rādhā-kṛṣṇa nā bhajiyā,
jāniyā śuniyā viṣa khāinu
Anyone who is not Kṛṣṇa conscious and who therefore does not engage in the service of the Lord is also paśu-ghna, for he is willingly drinking poison. Such a person cannot be interested in kṛṣṇa-kathā because he still has a desire for material sense gratification; he is not nivṛtta-tṛṣṇa. As it is said, traivargikās te puruṣā vimukhā hari-medhasaḥ. Those interested in trivarga—that is, in dharma, artha and kāma—are religious for the sake of achieving a material position with which to gain better facilities for sense gratification. Such persons are killing themselves by willingly keeping themselves in the cycle of birth and death. They cannot be interested in Kṛṣṇa consciousness.
(Srimad Bhagavatam----10:1:4----purport).

When discourses on kṛṣṇa-kathā take place between a liberated spiritual master and his disciple, others also sometimes take advantage of hearing these topics and also benefit. These topics are the medicine to stop the repetition of birth and death. The cycle of repeated birth and death, by which one takes on different bodies again and again, is called bhava or bhava-roga. If anyone, willingly or unwillingly, hears kṛṣṇa-kathā, his bhava-roga, the disease of birth and death, will certainly stop. Therefore kṛṣṇa-kathā is called bhavauṣadha, the remedy to stop the repetition of birth and death. Karmīs, or persons attached to material sense enjoyment, generally cannot give up their material desires, but kṛṣṇa-kathā is such a potent medicine that if one is induced to hear kṛṣṇa-kīrtana, he will certainly be freed from this disease. A practical example is Dhruva Mahārāja, who at the end of his tapasya was fully satisfied. When the Lord wanted to give Dhruva a benediction, Dhruva refused it.
(Srimad Bhagavatam----10:1:4----purport).

The mother naturally desires the welfare of the son. If a mother does not allow her son to search for Kṛṣṇa, she is called mā, which indicates māyā. By allowing her son to go as a sannyāsī and search for Kṛṣṇa, Śacīmātā instructs all mothers of the world. She indicates that all sons should become real devotees of Kṛṣṇa and should not stay at home under the care of an affectionate mother. This is supported by Śrīmad-Bhāgavatam (5.5.18):
gurur na sa syāt sva-jano na sa syāt
pitā na sa syāj jananī na sā syāt
daivaṁ na tat syān na patiś ca sa syān
na mocayed yaḥ samupeta-mṛtyum
"No one should become a spiritual master—nor a relative, father, mother, worshipable Deity or husband—if he cannot help a person escape the imminent path of death." Every living entity is wandering within the universe, subjected to the law of karma and transmigrating from one body to another and from one planet to another. Therefore the whole Vedic process is meant to save the wandering living entities from the clutches of māyā—birth, death, disease and old age. This means stopping the cycle of birth and death. This cycle can be stopped only if one worships Kṛṣṇa.
(Sri Caitanya Caritamrta-----2:3:181----purport).

To stop the cycle of birth and death, one has to understand Kṛṣṇa as He is. Simply by knowing Kṛṣṇa, one can stop the process of rebirth into this material world. By acting in Kṛṣṇa consciousness, one can return to Godhead. The highest perfection of life is for a father, mother, spiritual master, husband or any other family member to help others return home, back to Godhead. That is the most preferred welfare activity for the benefit of relatives. Therefore, Śacīmātā, although the mother of Nimāi Paṇḍita, Śrī Caitanya Mahāprabhu, considered all the facts and decided to allow her son to go out and search for Kṛṣṇa. At the same time, she made some arrangements in order that she might get news of all the activities of Śrī Caitanya Mahāprabhu.
(Sri Caitanya Caritamrta-----2:3:181----purport).

In this connection, Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura gives the following statement. The eastern side represents devotional service to Lord Kṛṣṇa. The southern side represents the process of fruitive activity (karma-kāṇḍa), which ends in material gain. The western side represents jñāna-kāṇḍa, the process of mental speculation, sometimes called siddhi-kāṇḍa. The northern side represents the speculative method, sometimes known as the mystic yoga system. It is only the eastern side, devotional service, that enables one to attain life's real goal. On the southern side, there are fruitive activities, by which one is subject to the punishment of Yamarāja. When one follows the system of fruitive activity, his material desires remain prominent. Consequently the results of this process are compared to wasps and drones. The living entity is bitten by the wasps and drones of fruitive activity and thus suffers in material existence birth after birth. One cannot become free from material desires by following this process. The propensity for material enjoyment never ends. Therefore the cycle of birth and death continues, and the spirit soul suffers perpetually.
(Sri Caitanya Caritamrta-----2:20:135----purport).

Due to our association with the modes of material nature, we get different types of bodies, good and bad. One cannot be liberated from the cycle of birth and death, known as transmigration of the soul, unless one is completely freed from all sinful activities. The best process, therefore, is to take to Kṛṣṇa consciousness. One cannot take to Kṛṣṇa consciousness without being freed from all sinful activities. Naturally one who is very serious about Kṛṣṇa consciousness is freed from all sinful activity. Consequently a devotee is never inclined to commit sins. If one is pressured by the law or obligations to give up sinful activity, one cannot do so. However, if one takes to Kṛṣṇa consciousness, he can very easily give up all sinful activity. This is confirmed herein.
(Sri Caitanya Caritamrta-----2:22:142----purport).

Māyāvādī philosophers, who have a poor fund of knowledge, simply dismiss the subject by explaining that kṛṣṇa means "black." Not understanding the qualities of Kṛṣṇa, these atheistic rascals do not accept Him as the Supreme Personality of Godhead. Although the Lord is described and accepted by great personalities, ācāryas and sages, the Māyāvādīs still do not appreciate Him. Unfortunately, at the present moment human society is so degraded that people cannot even provide themselves with life's daily necessities, yet they are captivated by Māyāvādī philosophers and are being misled. According to the Bhagavad-gītā, simply by understanding Kṛṣṇa one can get free from the cycle of birth and death. Tyaktvā dehaṁ punar janma naiti mām eti so ‘rjuna (B.G.4:9). Unfortunately this great science of Kṛṣṇa consciousness has been impeded by Māyāvādī philosophers, who are opposed to the personality of Kṛṣṇa. Those who are preaching this Kṛṣṇa consciousness movement must try to understand Kṛṣṇa from the statements given in the Bhakti-rasāmṛta-sindhu (The Nectar of Devotion).
(Sri Caitanya Caritamrta-----2:23:82-83----purport).

This verse refers to the association of pure devotees, the mercy of Kṛṣṇa and the rendering of devotional service. All these help one give up the association of nondevotees and the material opulence awarded by the external energy, māyā. A pure devotee is never attracted by material opulence, for he understands that wasting time to acquire material opulence is a misuse of the gift of human life. In Śrīmad-Bhāgavatam it is said, śrama eva hi kevalam (S.B.1:2:8). In the eyes of a devotee, politicians, social workers, philanthropists, philosophers and humanitarians are simply wasting their time, for human society is not freed from the cycle of birth and death by their activity and propaganda. These so-called philanthropists, politicians and philosophers have no knowledge because they do not know that there is life after death. Understanding that there is life after death is the beginning of spiritual knowledge.
(Sri Caitanya Caritamrta-----2:24:104----purport).

Not knowing the real science of life, a foolish person engages in the temporary activities of this life and thus becomes further entangled in the cycle of birth and death. He always desires material opulence, which can be attained by karma, jñāna and yoga. But when one is actually elevated to the devotional platform, he gives up all these desires. This is called anyābhilāṣitā-śūnya. Then one becomes a pure devotee.
(Sri Caitanya Caritamrta-----2:24:104----purport).

As clearly stated in the Bhagavad-gītā (3.9), yajñārthāt karmaṇo ‘nyatra loko ‘yaṁ karma-bandhanaḥ: if one does not act as a pure devotee, whatever acts he performs will produce reactions of fruitive bondage (karma-bandhanaḥ). Similarly, in Śrīmad-Bhāgavatam (5.5.4) it is said:
nūnaṁ pramattaḥ kurute vikarma
yad indriya-prītaya āpṛṇoti
na sādhu manye yata ātmano ‘yam
asann api kleśa-da āsa dehaḥ
"A materialistic person, madly engaged in activities for sense enjoyment, does not know that he is entangling himself in repeated birth and death and that his body, although temporary, is full of miseries." A viṣayī, a person blindly caught in a web of materialistic life, remains in the cycle of birth and death perpetually. Such a person cannot understand how to execute pure devotional service, and therefore he acts as a karmī, jñānī, yogī or something else, according to his desire, but he does not know that the activities of karma, jñāna and yoga simply bind one to the cycle of birth and death.
(Sri Caitanya Caritamrta-----3:6:199----purport).

Suppose one does not develop Kṛṣṇa consciousness in this human form of life. He will be thrown into the cycle of birth and death, involving 8,400,000 species of life, and his spiritual identity will remain lost. One does not know whether he is going to be a plant, or a beast, or a bird, or something like that, because there are so many species of life. The recommendation of Rūpa Gosvāmī for reviving our original Kṛṣṇa consciousness is that somehow or other we should apply our minds to Kṛṣṇa very seriously and thus also become fearless of death. After death we do not know our destination, because we are completely under the control of the laws of nature. Only Kṛṣṇa, the Supreme Personality of Godhead, is controller over the laws of nature. Therefore, if we take shelter of Kṛṣṇa seriously, there will be no fear of being thrown back into the cycle of so many species of life. A sincere devotee will surely be transferred to the abode of Kṛṣṇa, as affirmed in Bhagavad-gītā.
(Nectar of Devotion).