Skanda Purana 6.2.74.63

6.2.74.63

putrārthaṃ bhāryayā sārddhaṃ tadā dāsyāmi vāṃchitam ..
tadā samudrāścatvāraḥ sthāsyanti saphalāḥ svayam ..63..

with his wife for the sake of a son, then I will grant his desired wish; / then the four oceans will remain fruitful of their own accord.”