KAṬHA UPANISHAD · 1.2.20

अणोरणीयान्महतो महीयानात्माऽस्य जन्तोर्निहितो गुहायाम् ।
तमक्रतुः पश्यति वीतशोको
धातुप्रसादान्महिमानमात्मनः ॥ २०॥

aṇoraṇīyānmahato mahīyānātmā’sya jantornihito guhāyām ।
tamakratuḥ paśyati vītaśoko
dhātuprasādānmahimānamātmanaḥ ॥ 20॥

Finer than the fine, huger than the huge the Self hides in the secret heart of the creature: when a man strips himself of will and is weaned from sorrow, then he beholds Him, purified from the mental elements he sees the greatness of the Self-being.

Sri Aurobindo · CWSA 18, p. 112