Illusion

"Arjuna said,--'Thy birth is posterior; Vivaswat's birth is prior. How shall I understand then that thou
hadst first declared (it)?'

"The Holy One said,--'Many births of mine have passed away, O Arjuna, as also of thine. These all I
know, but thou dost not, O chastiser of foes. Though (I am) unborn and of essence that knoweth no
deterioration, though (I am) the lord of all creatures, still, relying on my own (material) nature I take
birth by my own (powers) of illusion. Whenever, O Bharata, loss of piety and the rise of impiety
occurreth, on those occasions do I create myself.

Bhishma Parva Section XXVIII