PURPORT

One might argue, "Since Bali Maharaja promised Vamanadeva only the land occupied by His steps, why did Lord Vamanadeva occupy the sky also?" In this regard, Srila Jiva Gosvami says that the steps include everything, downward and upward. When one stands up, he certainly occupies certain parts of the sky and certain portions of the earth below his feet. Thus there was nothing uncommon for the Supreme Personality of Godhead when He occupied the entire sky with His body.