In plain words
...came to be established as a divine ordinance. That these varṇas are the very limbs within the form of God Himself, this truth too was demonstrated in another way. They saw the fourfold varṇas, Brāhmaṇa, Kṣatriya, Vaiśya, Śūdra and the rest, as the various members of the Virāṭ form, that is, of God.
Taking the divine word declared in the Puruṣa Sūkta of the Ṛgveda, the truth will become clear.
'The Brāhmaṇa was His mouth; His two arms were made the Rājanya [Kṣatriya]; His two thighs became the Vaiśya; from His two feet the Śūdra was born' — thus, those of pure sāttvic nature, predominant in Jñāna, that is to say, the Brāhmaṇas, were God's mouth; those predominant in valour, with arm-strength, of sāttvic, rajasic and mixed nature, are the Kṣatriyas — His two arms; those mixed with rajas and of tamas-nature who are skilled in commerce are the Vaiśyas — His two thighs; and the Śūdras, predominant in bodily labour, that is, physical labourers, predominantly of tamas, were determined to be His feet — and thus the Ṛgveda has come describing [Him] as this wondrous, adorned form that is God Himself.
However, because these varṇas, which convey this sacred and profound meaning, have fallen into the grip of selfish persons and into the thinking of narrow-hearted people, and because those devoid of discernment have written commentaries on this as it occurred to them and done great harm to the world, today they wickedly argue that varṇas are mere fabrications devised so that the privileged might suppress the lowly. It is a matter of great regret that people fail to recognize that the varṇas are verily the divine form of Janārdana Himself in the form of the people, and the direct manifestation of the Supreme Lord, beautiful in every limb. As is the fortune of the Bharatiyas, even the Westerners, who fail to recognize the secret that God brings about the protection of the world through the limbs that are the varṇas, too,