Verse 17

विचारेणावदातेन पश्यत्यात्मानमात्मना ।इन्दुना शीतलेनान्तर्विश्वं खमिव तेजसा

In plain words

By spotless inquiry one sees the Self by the Self, as by the radiance of the cool moon one sees within the whole expanse of the sky.