SB 3.6.10

smaran viśva-sṛjām īśo
 vijñāpitam adhokṣajaḥ
virājam atapat svena
 tejasaiṣāṁ vivṛttaye
Word for word: 
smaran — remembering; viśva-sṛjām — of the demigods entrusted with the task of cosmic construction; īśaḥ — the Supreme Lord; vijñāpitam — as He was prayed for; adhokṣajaḥ — the Transcendence; virājam — the gigantic universal form; atapat — considered thus; svena — by His own; tejasā — energy; eṣām — for them; vivṛttaye — for understanding.
Translation: 
The Supreme Lord is the Supersoul of all the demigods entrusted with the task of constructing the cosmic manifestation. Being thus prayed to [by the demigods], He thought to Himself and thus manifested the gigantic form for their understanding.
Purport: 

The impersonalists are captivated by the gigantic universal form of the Supreme. They think that the control behind this gigantic manifestation is an imagination. Intelligent persons, however, can estimate the value of the cause by observing the wonders of the effects. For example, the individual human body does not develop from the womb of the mother independently but because the living entity, the soul, is within the body. Without the living entity, a material body cannot automatically take shape or develop. When any material object displays development, it must be understood that there is a spiritual soul within the manifestation. The gigantic universe has developed gradually, just as the body of a child develops. The conception that the Transcendence enters within the universe is, therefore, logical. As the materialists cannot find the soul and the Supersoul within the heart, similarly, for want of sufficient knowledge, they cannot see that the Supreme Soul is the cause of the universe. The Lord is therefore described in the Vedic language as avāṅ-mānasa-gocaraḥ, beyond the conception of words and minds.

Due to a poor fund of knowledge, the mental speculators try to bring the Supreme within the purview of words and minds, but the Lord refuses to be so intelligible; the speculator has no adequate words or mind to gauge the infinity of the Lord. The Lord is called adhokṣaja, or the person who is beyond perception by the blunt, limited potency of our senses. One cannot perceive the transcendental name or form of the Lord by mental speculation. The mundane Ph.D.’s are completely unable to speculate on the Supreme with their limited senses. Such attempts by the puffed up Ph.D’s are compared to the philosophy of the frog in the well. A frog in a well was informed of the gigantic Pacific Ocean, and he began to puff himself up in order to understand or measure the length and breadth of the Pacific Ocean. Ultimately the frog burst and died. The title Ph.D. can also be interpreted as Plough Department, a title meant for the tillers in the paddy field. The attempt of the tillers in the paddy field to understand the cosmic manifestation and the cause behind such wonderful work can be compared to the endeavor of the frog in the well to calculate the measurement of the Pacific Ocean.

The Lord can reveal Himself only to a person who is submissive and who engages in His transcendental loving service. The demigods controlling the elements and ingredients of universal affairs prayed to the Lord for guidance, and thus He manifested His gigantic form, as He did at the request of Arjuna.