Katha Upanishad 2.7

श्रवणायापि बहुभिर्यो न लभ्यः शृण्वन्तोऽपि बहवो यं न विद्युः | आश्चर्यो वक्ता कुशलोऽस्य लब्धाऽऽश्चर्यो ज्ञाता कुशलानुशिष्टः ॥

shravanayapi bahubhir yo na labhyah shrinvanto'pi bahavo yam na vidyuh | ashcharyo vakta kushalo'sya labdha''shcharyo jnata kushalanushishtah ||

That Self, which many are not even able to hear of, which many, even hearing, cannot comprehend — wonderful is the teacher, rare the one who finds It; wonderful is the knower, instructed by the skilful.

'जो आत्मा बहुतों को सुनने तक को नहीं मिलती, जिसे बहुत-से सुनकर भी नहीं जान पाते — आश्चर्य है उसका वक्ता, और कुशल है उसको पाने वाला; आश्चर्य है कुशल से सिखाया गया उसका ज्ञाता।'