“Krsna, known as Govinda, is the supreme controller. He has an eternal, blissful, spiritual body. He is the origin of all. He has no other origin, for He is the prime cause of all causes.” For the Lord’s existence there is no cause, for He is the cause of everything. He is in everything (mayā tatam idaṁ sarvam), He is expanded in everything, but He is not everything. He is acintya-bhedābheda, simultaneously one and different.

That is explained in this verse. In the material condition we have a conception of beginning, end and middle, but for the Supreme Personality of Godhead there are no such things. The universal cosmic manifestation is also the virāṭ-rūpa that was shown to Arjuna in Bhagavad-gītā. Therefore, since the Lord is present everywhere and all the time, He is the Absolute Truth and the greatest. He is complete in greatness. God is great, and how He is great is explained here.
Srimad-Bhagavatam 8.1.11