Srimad-Bhagavatam: Canto 5 - Chapter 1 - Verse 1
स होवाचस एष देहात्ममानिनां सत्त्वादिगुणविशेषविकल्पितकुशलाकुशलसमवहारविनिर्मितविविधदेहावलिभिर्वियोगसंयोगाद्यनादिसंसारानुभवस्य द्वारभूतेनषडिन्द्रियवर्गेण तस्मिन्दुर्गाध्ववदसुगमेऽध्वन्यापतित ईश्वरस्य भगवतो विष्णोर्वशवर्तिन्या मायया जीवलोकोऽयं यथा वणिक्सार्थोऽर्थपर: स्वदेहनिष्पादितकर्मानुभव: श्मशानवदशिवतमायां संसाराटव्यां गतो नाद्यापि विफलबहुप्रतियोगेहस्तत्तापोपशमनीं हरिगुरुचरणारविन्दमधुकरानुपदवीमवरुन्धे ॥ १ ॥
sa hovācasa eṣa dehātma-mānināṁ sattvādi-guṇa-viśeṣa-vikalpita-kuśalāku-śala-samavahāra-vinirmita-vividha-dehāvalibhir viyoga-saṁyogādy-anādi-saṁsārānubhavasya dvāra-bhūtena ṣaḍ-indriya-vargeṇa tasmin durgādhvavad asugame ’dhvany āpatita īśvarasya bhagavato viṣṇor vaśa-vartinyā māyayā jīva-loko ’yaṁ yathā vaṇik-sārtho ’rtha-paraḥ sva-deha-niṣpādita-karmānubhavaḥ śmaśānavad aśivatamāyāṁ saṁsārāṭavyāṁ gato nādyāpi viphala-bahu-pratiyogehas tat-tāpopaśamanīṁ hari-guru-caraṇāravinda-madhukarānupadavīm avarundhe.
When King Parīkṣit asked Śukadeva Gosvāmī about the direct meaning of the material forest, Śukadeva Gosvāmī replied as follows: My dear King, a man belonging to the mercantile community [vaṇik] is always interested in earning money. Sometimes he enters the forest to acquire some cheap commodities like wood and earth and sell them in the city at good prices. Similarly, the conditioned soul, being greedy, enters this material world for some material profit. Gradually he enters the deepest part of the forest, not really knowing how to get out. Having entered the material world, the pure soul becomes conditioned by the material atmosphere, which is created by the external energy under the control of Lord Viṣṇu. Thus the living entity comes under the control of the external energy, daivī māyā. Living independently and bewildered in the forest, he does not attain the association of devotees who are always engaged in the service of the Lord. Once in the bodily conception, he gets different types of bodies one after the other under the influence of material energy and impelled by the modes of material nature [sattva-guṇa, rajo-guṇa and tamo-guṇa]. In this way the conditioned soul goes sometimes to the heavenly planets, sometimes to the earthly planets and sometimes to the lower planets and lower species. Thus he suffers continuously due to different types of bodies. These sufferings and pains are sometimes mixed. Sometimes they are very severe, and sometimes they are not. These bodily conditions are acquired due to the conditioned soul’s mental speculation. He uses his mind and five senses to acquire knowledge, and these bring about the different bodies and different conditions. Using the senses under the control of the external energy, māyā, the living entity suffers the miserable conditions of material existence. He is actually searching for relief, but he is generally baffled, although sometimes he is relieved after great difficulty. Struggling for existence in this way, he cannot get the shelter of pure devotees, who are like bumblebees engaged in loving service at the lotus feet of Lord Viṣṇu.
The most important information in this verse is hari-guru-caraṇa-aravinda-madhukara-anupadavīm. In this material world the conditioned souls are baffled by their activities, and sometimes they are relieved after great difficulty. On the whole the conditioned soul is never happy. He simply struggles for existence. Actually his only business is to accept the spiritual master, the guru, and through him he must accept the lotus feet or the Lord. This is explained by Śrī Caitanya Mahāprabhu: guru-kṛṣṇa-prasāde pāya bhakti-latā-bīja. People struggling for existence in the forests or cities of the material world are not actually enjoying life. They are simply suffering different pains and pleasures, generally pains that are always inauspicious. They try to gain release from these pains, but they cannot due to ignorance. For them it is stated in the Vedas: tad-vijñānārthaṁ sa gurum evābhigacchet. When the living entity is lost in the forest of the material world, in the struggle for existence, his first business is to find a bona fide guru who is always engaged at the lotus feet of the Supreme Personality of Godhead, Viṣṇu. After all, if he is at all eager to be relieved of the struggle for existence, he must find a bona fide guru and take instructions at his lotus feet. In this way he can get out of the struggle. Since the material world is compared herein to a forest, it may be argued that in Kali-yuga modern civilization is mainly situated in the cities. A great city, however, is like a great forest. Actually city life is more dangerous than life in the forest. If one enters an unknown city without friend or shelter, living in that city is more difficult than living in a forest. There are many big cities all over the surface of the globe, and wherever one looks he sees the struggle for existence going on twenty-four hours a day. People rush about in cars going seventy and eighty miles an hour, constantly coming and going, and this sets the scene of the great struggle for existence. One has to rise early in the morning and travel in that car at breakneck speed. There is always the danger of an accident, and one has to take great care. In his automobile, the living entity is full of anxieties, and his struggle is not at all auspicious. Apart from human beings, other species like cats and dogs are also struggling very hard day and night for existence. Thus the struggle for existence continues, and the conditioned soul changes from one position to another. For a while, he is a child, but he has to become a boy. From a boy, he has to change into a youth, and from youth to manhood and old age. Finally, when the body is no longer workable, he has to accept a new body in a different species. Giving up the body is called death, and accepting another body is called birth. The human form is an opportunity to take shelter of the bona fide spiritual master and, through him, the Supreme Lord. This Kṛṣṇa consciousness movement has been started to give an opportunity to all the members of human society, who are misled by foolish leaders. No one can get out of this struggle for existence, which is full of miseries, without accepting a pure devotee of the Lord. The material attempt changes from one position to another, and no one actually gains relief from the struggle for existence. The only resort is the lotus feet of a bona fide spiritual master, and, through him, the lotus feet of the Lord.