SB 10.14.16
atraiva maya-dhamanavatare
hy asya prapañcasya bahih sphutasya
krtsnasya cantar jathare jananya
mayatvam eva prakati-krtam te
Translation:
My dear Lord, in this incarnation You have proved that You are the supreme controller of Maya. Although You are now within this universe, the whole universal creation is within Your transcendental body a fact You demonstrated by exhibiting the universe within Your abdomen before Your mother, Yasoda.
Purport:
Lord Brahma here describes the inconceivable spiritual potency of the Lord. We may find a pot within a house, but we can hardly expect to find the house within the same pot. By the Lord’s spiritual potency, however, He can appear within this universe and simultaneously exhibit all the universes within His body. One may argue that since the universes seen by mother Yasoda within Lord Krsna’s abdomen were within the Lord’s body, they are different from the illusory material universes manifest externally. Here Lord Brahma refutes that argument, however. Lord Krsna is maya-dhamana, the supreme controller of illusion. By the Lord’s own supreme mystic potency, He can bewilder even illusion herself, and thus the Lord actually exhibited all the material universes within His body. This is mayatvam, the supreme bewildering potency of the Personality of Godhead.