Bhagavatapurana 6.5.5

6.5.5

tepire tapa evograṃ pitrādeśena yantritāḥ /
prajāvivṛddhaye yattān devarṣistān dadarśa ha //

4. Soon after bathing in, and drinking of, that water, they had their heart cleansed of all impurity and further had a settled mind for the righteous course of Paramahamsas. 5. Still feeling themselves bound by the command of their father they performed austere tapas, intent on the increase of population; (by God's will indeed) the divine sage Narada saw them thus exerting themselves to the utmost.