tÄḥ putram aá¹…kam Äropya
sneha-snuta-payodharÄḥ
hará¹£a-vihvalitÄtmÄnaḥ
siṣicur netrajair jalaiḥ
This is mentioned to show that he greatly respected the seven because they were sisters of his mother Devaki. Vasudeva actually had eighteen wives and he offered respects to all of them as his mothers.