O King Parīkṣit, from the navel of the Supreme Personality of Godhead was generated a golden lotus, on which the four-faced Lord Brahmā took his birth.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तस्य नाभेः समभवत्पद्मकोशो हिरण्मयः । तस्मिन् जज्ञे महाराज स्वयम्भूश्चतुराननः
tasya nābheḥ samabhavatpadmakośo hiraṇmayaḥ | tasmin jajñe mahārāja svayambhūścaturānanaḥ
SB 9.1.9