PURPORT

Vamanadeva first expanded Himself to the universal form and then reduced Himself to the original Vamana-rupa. Thus He acted exactly like Lord Krsna, who, at the request of Arjuna, first showed His universal form and later resumed His original form as Krsna. The Lord can assume any form He likes, but His original form is that of Krsna (krsnas tu bhagavan svayam). According to the capacity of the devotee, the Lord assumes various forms so that the devotee can handle Him. This is His causeless mercy. When Lord Vamanadeva resumed His original form, Lord Brahma and his associates collected various paraphernalia for worship with which to please Him.