tata atmani loke ca
drastasi mam tatam brahman
mayi lokams tvam atmanah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O Brahma, when you are absorbed in devotional service, in the course of your creative activities, you will see Me in you and throughout the universe, and you will see that you yourself, the universe and the living entities are all in Me.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is cited herein by the Lord that during his daytime Brahma would see Him as Lord Sri Krsna. He would appreciate how the Lord expanded Himself into all the calves during His childhood at Vrndavana, he would know how Yasodamayi saw all the universes and planetary systems within the mouth of Krsna during His playful childhood pastimes, and he would also see that there are many millions of Brahmas during the appearance of Lord Krsna in Brahma’s daytime. But all these manifestations of the Lord, appearing everywhere in His eternal, transcendental forms, cannot be understood by anyone but the pure devotees, who are always engaged in devotional service to the Lord and are fully absorbed in the Lord. The high qualifications of Brahma are also indicated herein.