Natyashastra
वाद्यवृत्तिविभागार्थं वक्त्रपाणिर्विधीयते । तन्त्र्योजःकरणार्थं तु भवेच्च परिघट्टना ॥ १९॥
The act of directing the mouth and hand is designated for the division of the musical rhythms. The act of striking the instrument is intended for the creation of sound through the string.
english translation
vAdyavRttivibhAgArthaM vaktrapANirvidhIyate । tantryojaHkaraNArthaM tu bhavecca parighaTTanA ॥ 19॥
hk transliteration by Sanscript