Charak Samhita
जानन्नपि मृदोऽभावात् कुम्भकृन्न प्रवर्तते। श्रूयतां चेदमध्यात्ममात्मज्ञानबलं महत् ॥२०॥
A potter cannot function in the absence of clay even when he is knowledgeable and skilled. Listen to this spiritual wisdom- a greatly powerful knowledge of the soul.
english translation
jAnannapi mRdo'bhAvAt kumbhakRnna pravartate। zrUyatAM cedamadhyAtmamAtmajJAnabalaM mahat ॥20॥
hk transliteration by Sanscript