iti mÄ«mÄá¹satas tasya
brahmaṇaḥ saha sūnubhiḥ
bhagavÄn yajña-puruá¹£o
jagarjÄgendra-sannibhaḥ
iti - thus; mÄ«mÄá¹sataḥ - while deliberating; tasya - his; brahmaṇaḥ - of BrahmÄ; saha - along with; sÅ«nubhiḥ - his sons; bhagavÄn - the Personality of Godhead; yajña - Lord Viṣṇu; puruá¹£aḥ - the Supreme Person; jagarja - resounded; aga-indra - great mountain; sannibhaḥ - like.
It appears that great hills and mountains also have their roaring power because they are also living entities. The volume of the sound vibrated is in proportion to the size of the material body. While BrahmÄ was guessing about the appearance of the Lord’s incarnation as a boar, the Lord confirmed BrahmÄ’s contemplation by roaring with His gorgeous voice.