Srimad Bhagavatam Canto 10, Chapter 24, Text 35

SB 10.24.35

krsnas tv anyatamam rupam
 gopa-visrambhanam gatah
sailo ’smiti bruvan bhuri
 balim adad brhad-vapuh
Krsna then assumed an unprecedented, huge form to instill faith in the cowherd men. Declaring “I am Govardhana Mountain!” He ate the abundant offerings.
In Chapter Twenty-four of Krsna, the Supreme Personality of Godhead, Srila Prabhupada writes: “When everything was complete, Krsna assumed a great transcendental form and declared to the inhabitants of Vrndavana that He was Himself Govardhana Hill in order to convince the devotees that Govardhana Hill and Krsna Himself are identical. Then Krsna began to eat all the food offered there. The identity of Krsna and Govardhana Hill is still honored, and great devotees take rocks from Govardhana Hill and worship them exactly as they worship the Deity of Krsna in the temples. The followers of the Krsna consciousness movement may therefore collect small rocks or pebbles from Govardhana Hill and worship them at home, because this worship is as good as Deity worship.”
Lord Krsna had induced the residents of Vrndavana to assume a significant risk on His behalf. He convinced them to neglect a sacrifice to what is, after all, the powerful government of the universe and to worship a hill called Govardhana instead. The cowherd community did all this simply out of love for Krsna, and now to convince them that their decision was correct, Lord Krsna appeared in an unprecedented, huge transcendental form and demonstrated that He Himself was Govardhana Hill.
Srimad Bhagavatam Canto 10, Chapter 24, Text 34
Srimad Bhagavatam Canto 10, Chapter 24, Text 36