SB 5.18.31
yad-rupam etan nija-mayayarpitam
artha-svarupam bahu-rupa-rupitam
sankhya na yasyasty ayathopalambhanat
tasmai namas te ’vyapadesa-rupine
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
My dear Lord, this visible cosmic manifestation is a demonstration of Your own creative energy. Since the countless varieties of forms within this cosmic manifestation are simply a display of Your external energy, this virat-rupa [universal body] is not Your real form. Except for a devotee in transcendental consciousness, no one can perceive Your actual form. Therefore I offer my respectful obeisances unto You.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Mayavadi philosophers think the universal form of the Lord to be real and His personal form illusory. We can understand their mistake by a simple example. A fire consists of three elements: heat and light, which are the energy of the fire, and the fire itself. Anyone can understand that the original fire is the reality and that the heat and light are simply the fire’s energy. Heat and light are the formless energies of fire, and in that sense they are unreal. Only the fire has form, and therefore it is the real form of the heat and light. As Krsna states in Bhagavad-gita (9.4), maya tatam idam sarvam jagad avyakta-murtina: “By Me, in My unmanifested form. this entire universe is pervaded.” Thus the impersonal conception of the Lord is like the expansion of heat and light from a fire. In Bhagavad-gita the Lord also says, mat-sthani sarva-bhutani na caham tesv avasthitah: the entire material creation is resting on Krsna’s energy, either material, spiritual or marginal, but because His form is absent from the expansion of His energy, He is not personally present. This inconceivable expansion of the Supreme Lord’s energy is called acintya-sakti. Therefore no one can understand the real form of the Lord without becoming His devotee.