O sinless Brahmā, you may know from Me that it was I who first ordered you to undergo penance when you were perplexed in your duty. Such penance is My heart and soul, and therefore penance and I are nondifferent.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
सृजामि तपसैवेदं ग्रसामि तपसा पुनः । बिभर्मि तपसा विश्वं वीर्यं मे दुश्चरं तपः
sṛjāmi tapasaivedaṃ grasāmi tapasā punaḥ | bibharmi tapasā viśvaṃ vīryaṃ me duścaraṃ tapaḥ
SB 2.9.23