This is a quotation from Bhagavad-gītā (7.16). The word sukṛtinaḥ is very important in this verse. Su means "auspicious," and kṛtī means "meritorious" or "regulated." Unless one follows the regulative principles of religious life, human life is no different from animal life. Religious life means following the principles of varṇa and āśrama. In the Viṣṇu Purāṇa it is said:

varṇāśramācāra-vatā
puruṣeṇa paraḥ pumān
viṣṇur ārādhyate panthā
nānyat tat-toṣa-kāraṇam

According to religious life, society is divided into four social divisions-brāhmaṇa, kṣatriya, vaiśya and śūdra-and four spiritual divisions-brahmacarya, gṛhastha, vānaprastha and sannyāsa. One needs to be trained to become a brāhmaṇa, kṣatriya, vaiśya or śūdra, just as one is trained to become an engineer, doctor or lawyer. Those who are properly trained can be considered human beings; if one is not trained socially and spiritually-that is, if one is uneducated and unregulated-his life is on the animal platform. Among animals there is no question of spiritual advancement. Spiritual life can be attained by proper training-either by following the principles of varṇa and āśrama or by being directly trained in the bhakti school by the methods of śravaṇaṁ kīrtanaṁ viṣṇoḥ smaraṇaṁ pāda-sevanamarcanaṁ vandanaṁ dāsyaṁ sakhyam ātma-nivedanam. Without being trained, one cannot be sukṛtī, auspicious. In this verse Kṛṣṇa says that people approach Him when in distress, in need of money or when actually inquisitive to understand the Supreme Being or the original source of everything. Some people approach Him in the pursuit of knowledge of the Absolute Truth, and others approach Him when they are distressed, like the devotee Gajendra. Others are inquisitive, like the great sages headed by Sanaka, and others need money, like Dhruva Mahārāja. Śukadeva Gosvāmī approached the Lord when he pursued knowledge. All these great personalities thus took to the devotional service of the Supreme Personality of Godhead, Kṛṣṇa.