SB 4.15.2

tad dṛṣṭvā mithunaṁ jātam
 ṛṣayo brahma-vādinaḥ
ūcuḥ parama-santuṣṭā
 viditvā bhagavat-kalām
Synonyms: 
tat — that; dṛṣṭvā — seeing; mithunam — couple; jātam — born; ṛṣayaḥ — the great sages; brahma-vādinaḥ — very learned in Vedic knowledge; ūcuḥ — said; parama — very much; santuṣṭāḥ — being pleased; viditvā — knowing; bhagavat — of the Supreme Personality of Godhead; kalām — expansion.
Translation: 
The great sages were highly learned in Vedic knowledge. When they saw the male and female born of the arms of Vena’s body, they were very pleased, for they could understand that the couple was an expansion of a plenary portion of Viṣṇu, the Supreme Personality of Godhead.
Purport: 

The method adopted by the great sages and scholars, who were learned in Vedic knowledge, was perfect. They removed all the reactions of King Vena’s sinful activities by seeing that King Vena first gave birth to Bāhuka, described in the previous chapter. After King Vena’s body was thus purified, a male and female came out of it, and the great sages could understand that this was an expansion of Lord Viṣṇu. This expansion, of course, was not viṣṇu-tattva but a specifically empowered expansion of Lord Viṣṇu known as āveśa.