Shat.Upa 01.03

अथ कबन्धी कात्यायनः उपेत्य पप्रच्छ। भगवन् कुतो ह वा इमाः प्रजाः प्रजायन्त इति। तस्मै स होवाच प्रजाकामो ह वै प्रजापतिः। स तपोऽतप्यत ॥३॥

atha kabandhī kātyāyanaḥ upetya papraccha। bhagavan kuto ha vā imāḥ prajāḥ prajāyanta iti। tasmai sa hovāca prajākāmo ha vai prajāpatiḥ। sa tapo'tapyata ॥3॥

[अथ (atha) - then; कबन्धी (kabandhī) - Kabandhi; कात्यायनः (kātyāyanaḥ) - Katyayana; उपेत्य (upetya) - approaching; पप्रच्छ (papraccha) - asked; भगवन् (bhagavan) - O revered one; कुतः (kutaḥ) - from where; ह (ha) - indeed; वा (vā) - or; इमाः (imāḥ) - these; प्रजाः (prajāḥ) - creatures; प्रजायन्ते (prajāyante) - are born; इति (iti) - thus; तस्मै (tasmai) - to him; सः (saḥ) - he; उवाच (uvāca) - said; प्रजाकामः (prajākāmaḥ) - desiring progeny; ह (ha) - indeed; वै (vai) - truly; प्रजापतिः (prajāpatiḥ) - Prajapati; सः (saḥ) - he; तपः (tapaḥ) - austerity; अतप्यत (atapyata) - performed;]

Then Kabandhi Katyayana, having approached, asked: "O revered one, from where indeed are these creatures born?" To him, he said: "Prajapati, indeed desiring progeny, performed austerity."

Bhāṣya 01.03

Lord Viṣṇu is referred to as 'prajāpati', the lord of the people, because he protects them.

प्रजानां पालनाद्विष्णुः प्रजापतिरितीरितः।

prajānāṃ pālanādviṣṇuḥ prajāpatiritīritaḥ।

[प्रजानाम् (prajānām) - of the subjects; पालनात् (pālanāt) - by the protection; विष्णुः (viṣṇuḥ) - Viṣṇu; प्रजापतिः (prajāpatiḥ) - lord of the subjects; इति (iti) - thus; ईरितः (īritaḥ) - is called;]

(Viṣṇu is called the lord of the subjects by the protection of the subjects.)

Lord Viṣṇu is referred to as 'prajāpati', the lord of the people, because he protects them.