Lord Brahmā underwent penances for one thousand years by the calculations of the demigods. He heard this transcendental vibration from the sky, and he accepted it as divine. Thus he controlled his mind and senses, and the penances he executed were a great lesson for the living entities. Thus he is known as the greatest of all ascetics.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
दिव्यं सहस्राब्दममोघदर्शनो जितानिलात्मा विजितोभयेन्द्रियः । अतप्यत स्माखिललोकतापनं तपस्तपीयांस्तपतां समाहितः
divyaṃ sahasrābdamamoghadarśano jitānilātmā vijitobhayendriyaḥ | atapyata smākhilalokatāpanaṃ tapastapīyāṃstapatāṃ samāhitaḥ
SB 2.9.8