In accordance with their father’s order to beget children, the second group of sons also went to Nārāyaṇa-saras, the same place where their brothers had previously attained perfection by following the instructions of Nārada. Undertaking great vows of austerity, the Savalāśvas remained at that holy place.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तेऽपि पित्रा समादिष्टाः प्रजासर्गे धृतव्रताः । नारायणसरो जग्मुर्यत्र सिद्धाः स्वपूर्वजाः
te'pi pitrā samādiṣṭāḥ prajāsarge dhṛtavratāḥ | nārāyaṇasaro jagmuryatra siddhāḥ svapūrvajāḥ
SB 6.5.25