The whole is the Supreme Personality of Godhead in His virat-rupa, or universal form. The brahmanas, ksatriyas, vaisyas and sudras are respectively the mouth, arms, abdomen and legs of the universal form of the Lord

Expressions researched:
"The whole is the Supreme Personality of Godhead in His virāṭ-rūpa, or universal form. The brāhmaṇas, kṣatriyas, vaiśyas and śūdras are respectively the mouth, arms, abdomen and legs of the universal form of the Lord"

Srimad-Bhagavatam

SB Canto 4

The whole is the Supreme Personality of Godhead in His virāṭ-rūpa, or universal form. The brāhmaṇas, kṣatriyas, vaiśyas and śūdras are respectively the mouth, arms, abdomen and legs of the universal form of the Lord. As long as they are engaged in the service of the complete whole, their position is secure, otherwise they fall down from their respective positions and become degraded.

SB 4.6.44, Translation and Purport

My dear lord, Your Lordship has introduced the system of sacrifices through the agency of Dakṣa, and thus one may derive the benefits of religious activities and economic development. Under your regulative principles, the institution of the four varṇas and āśramas is respected. The brāhmaṇas therefore vow to follow this system strictly.

The Vedic system of varṇa and āśrama is never to be neglected, for these divisions are created by the Supreme Lord Himself for the upkeep of social and religious order in human society. The brāhmaṇas, as the intelligent class of men in society, must vow to steadily respect this regulative principle. The tendency in this age of Kali to make a classless society and not observe the principles of varṇa and āśrama is a manifestation of an impossible dream. Destruction of the social and spiritual orders will not bring fulfillment of the idea of a classless society. One should strictly observe the principles of varṇa and āśrama for the satisfaction of the creator, for it is stated in the Bhagavad-gītā by Lord Kṛṣṇa that the four orders of the social system—brāhmaṇas, kṣatriyas, vaiśyas and śūdras—are His creation. They should act according to the regulative principles of this institution and satisfy the Lord, just as different parts of the body all engage in the service of the whole. The whole is the Supreme Personality of Godhead in His virāṭ-rūpa, or universal form. The brāhmaṇas, kṣatriyas, vaiśyas and śūdras are respectively the mouth, arms, abdomen and legs of the universal form of the Lord. As long as they are engaged in the service of the complete whole, their position is secure, otherwise they fall down from their respective positions and become degraded.