Mandukya Karika, verse 4.26

Text

चित्तं न संस्पृशत्यर्थं नार्थाभासं तथैव च ।
अभूतो हि यतश्चार्थो नार्थाभासस्ततः पृथक् ॥ २६ ॥

cittaṃ na saṃspṛśatyarthaṃ nārthābhāsaṃ tathaiva ca |
abhūto hi yataścārtho nārthābhāsastataḥ pṛthak || 26 ||

26. The mind is not related to the (external) object Nor are the ideas which appear as external objects, reflections upon the mind. It is so because the objects are non-existent and the ideas (which appear as external objects) are not separate from the mind.

Shankara Bhashya (commentary)

Because there are no external objects as cause, the mind does not relate itself to external objects which are supposed to be the cause of the subjective impression. Nor is the mind related to the ideas which appear as external objects, as the mind, like1 the dream-mind, is identical with such ideas. It2 is because the external objects such as sound, etc., perceived in the waking state, are as unreal as dream-objects, for3 reasons stated already. Another reason is that the ideas appearing as external objects are not different from the mind. It4 is the mind alone which, as in dream, appears as external objects such as the jar, etc.