Bhagavatapurana 10.3.37

10.3.37

tadā vāṃ parituṣṭo 'ham amunā vapuṣānaghe /
tapasā śraddhayā nityaṃ bhaktyā ca hṛdi bhāvitaḥ //

37. & 38. Then, O sinless one, contemplated at heart in constant tapas, faith and devotion and highly delighted with you, did I, the foremost dispenser of boons, reveal Myself, in this very form, to bestow on you the object of your desire. When prompted to ask for a boon, a son like me was desired by you.