Atharvaveda 9.10.13

9.10.13

pr̥chā́mi tvā páram ántaṃ pr̥thivyā́ḥ pr̥chā́mi vŕ̥ṣṇo áśvasya rétaḥ |
pr̥chā́mi víśvasya bhúvanasya nā́bhiṃ pr̥chā́mi vācáḥ paramáṃ vyòma ||13||

I ask of thee the extreme (pára) end of the earth; I ask the seed of the male (vṛ́ṣan) horse; I ask the navel of all existence; I ask the highest (paramá) firmament (vyòman) of speech.