Slokam 9

Sages such as Sukra,  and scions of Bhrighu lineage,  behold the Vamana avatar.

Extracts from Wikipedia

Maharishi Bhrigu (Sanskrit: Bhṛgu) was one of the seven great sages, the Saptarshis, one of the many Prajapatis (the facilitators of Creation) created by Brahma.^[1] The first compiler of predictive astrology, and also the author of Bhrigu Samhita, the astrological (Jyotish) classic, Bhrigu is considered a Manasa Putra ("mind-born-son") of Brahma. The adjectival form of the name, Bhargava, is used to refer to the descendants and the school of Bhrigu. According to Manusmriti, Bhrigu was a compatriot of and lived during the time of Manu, the Hindu progenitor of humanity.^[2] Bhrigu had his Ashram (Hermitage) on the Vadhusar River, a tributary of the Drishadwati River near Dhosi Hill in the Vedic state of Brahmavarta,^[3] presently on the border of Haryana and Rajasthan in India.^[4] Along with Manu, Bhrigu had made important contributions to Manusmriti, which was constituted out of a sermon to a congregation of saints in the state of Brahmavarta, after the great floods in this area,^[5] nearly 10,000 years ago.^[6] As per Skanda Purana, Bhrigu migrated to Bhrigukutch, modern Bharuch on the banks of the Narmada river in Gujarat, leaving his son Chyavana at Dhosi Hill.

He was married to Khyati, one of the nine daughters of sage Kardama.^[7] They had two sonsnamed Dhata and Vidhata. He had one more son with Kavyamata (Usana), who is better known than Bhrigu himself – Shukra, learned sage and guru of the asuras. The sage Chyavana is also said to be his son with Puloma, as is the folk hero Mrikanda.^[8] [Maha:1.5] One of his descendants was sage Jamadagni, who in turn was the father of sage Parashurama, considered an avatar of Vishnu.^[9][10][11]

The enlightened sages,  at the site,  without knowing who Vamana was,  but recognizing that this is someone of great attainment,  escort Him to Bali. 

Bali, being a sincere Bhaktha,  washes His feet with servitude.  This is the contradiction in the psyche of an asura.  He trusts the supreme Paramathma.  He knows that the ultimate power lies elsewhere.  Yet the asura,  cannot suppress his instinct to plunder and act in direct contradiction to the dharmic teachings of the Paramathma.

Bali sprinkles the water on His head.  Sri Bhattadri explains that the water could transform even holy waters into more sacred efficacy.

May we never develop an ego that will prevent us from acknowledging that our every breath is an endowment.