SB 3.21.51
yo ’rkendv-agnindra-vayunam
yama-dharma-pracetasam
rupani sthana adhatse
tasmai suklaya te namah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When necessary, You assume the part of the sun-god; the moon-god; Agni, the god of fire; Indra, the lord of paradise; Vayu, the wind-god; Yama, the god of punishment; Dharma, the god of piety; and Varuna, the god presiding over the waters. All obeisances to you, who are none other than Lord Visnu!
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Since the sage Kardama was a brahmana and Svayambhuva was a ksatriya, the sage was not supposed to offer obeisances to the King because socially his position was greater than the King’s. But he offered his obeisances to Svayambhuva Manu because as Manu, king and emperor, he was the representative of the Supreme Lord. The Supreme Lord is always worshipable, regardless of whether one is a brahmana, a ksatriya or a sudra. As the representative of the Supreme Lord, the King deserved respectful obeisances from everyone.