KAṬHA UPANISHAD · 1.2.8

न नरेणावरेण प्रोक्त एष
सुविज्ञेयो बहुधा चिन्त्यमानः ।
अनन्यप्रोक्ते गतिरत्र नास्ति
अणीयान् ह्यतर्क्यमणुप्रमाणात् ॥ ८॥

na nareṇāvareṇa prokta eṣa
suvijñeyo bahudhā cintyamānaḥ ।
ananyaprokte gatiratra nāsti
aṇīyān hyatarkyamaṇupramāṇāt ॥ 8॥

An inferior man cannot tell you of Him; for thus told thou canst not truly know Him, since He is thought of in many aspects. Yet unless told of Him by another thou canst not find thy way there to Him; for He is subtler than subtlety and that which logic cannot reach.

Sri Aurobindo · CWSA 18, p. 109