None knoweth whence creation has arisen;
And whether he has or has not produced it:
He who surveys it in the highest heaven,
He only knows, or haply he may not know.
-Last part of naasadiiya sukta (Hymn of Creation) from Rigved's X.129
Translation quoted from Macdonnell's Vedic Mythology, 1897, as given in "A source book of Indian Philosophy"
Eds. Radhakrishnan and Moore. Full hymn with its translation can be found here