SB 11.6.16
tvattah puman samadhigamya yayasya viryam
dhatte mahantam iva garbham amogha-viryah
so ’yam tayanugata atmana anda-kosam
haimam sasarja bahir avaranair upetam
Translation:
My dear Lord, the original purusa-avatara, Maha-Visnu, acquires His creative potency from You. Thus with infallible energy He impregnates material nature, producing the mahat-tattva. Then the mahat-tattva, the amalgamated material energy, endowed with the potency of the Lord, produces from itself the primeval golden egg of the universe, which is covered by various layers of material elements.
Purport:
In the previous verses the supremacy of the Personality of Godhead has been established in relation to the living entity and material nature. In this verse it is clearly stated that Lord Krsna is the source of the greatest Visnu incarnation, Maha-Visnu, and that Maha-Visnu acquires His creative potency from Lord Krsna. It would therefore be foolish to surmise that Lord Krsna is an expansion of Visnu. In this regard the opinion of the demigods, headed by Brahma, can be taken as final.