The Blessed Lord said: They speak of an imperishable ashvattha tree with its root above and its branches below, whose leaves are the hymns; whoever knows it is a knower of the Vedas.
श्रीभगवानुवाच | ऊर्ध्वमूलमधःशाखमश्वत्थं प्राहुरव्ययम् | छन्दांसि यस्य पर्णानि यस्तं वेद स वेदवित् ||१५-१||