Śatapatha Brāhmaṇa ("of a hundred paths") 2.1.1.7

2.1.1.7

athākhukarīṣaṃ sambharati | ākhavo ha vā asyai pṛthivyai rasaṃ vidustasmātte 'dho 'dha imām pṛthivīṃ carantaḥ pīviṣṭhā asyai hi rasaṃ viduste yatra te 'syai pṛthivyai rasaṃ vidustata utkiranti tadasyā evainametatpṛthivyai rasena samardhayati tasmādākhukarīṣaṃ sambharati purīṣya iti vai tamāhuryaḥ śriyaṃ gacati samānaṃ vai purīṣaṃ ca karīṣaṃ ca tadetasyaivāvaruddhai tasmādākhukarīṣaṃ sambharati

He then brings (the earth of) a mole-hill (âkhu-karîsha). The moles certainly know the savour of this earth: hence, by entering deeper and deeper into this earth, they (grow) very fat, knowing, as they do, its savour; and wherever they know the savour of this earth to be, there they cast it up. Hence he thereby supplies it (the fire) with the savour of this earth: that is why he brings a molehill. Moreover, they say of one who has attained prosperity (or splendour, sri) that he is purîshya; and purîsha and karîsha doubtless mean one and the same thing: it is, therefore, for his (Agni's or the sacrificer's) attainment of splendour (sri) that he brings a mole-hill.