Mandukya Karika, verse 4.54

Text

एवं न चित्तजा धर्माश्चित्तं वापि न धर्मजम् ।
एवं हेतुफलाजातिं प्रविशन्ति मनीषिणः ॥ ५४ ॥

evaṃ na cittajā dharmāścittaṃ vāpi na dharmajam |
evaṃ hetuphalājātiṃ praviśanti manīṣiṇaḥ || 54 ||

54. Thus (external) appearances (objects) are not caused by the mind nor is the mind produced by them. Hence men of discrimination hold the principle of the absolute non-evolution or negation of causality.

Shankara Bhashya (commentary)

Thus, for1 reasons already stated, the mind is verily of the nature of the essence of the Self. External2 objects are not caused by the mind nor is the mind the product of the external objects. That is because all (external) entities are mere appearances in Consciousness. Thus neither the (so-called) effect comes from the (so-called) cause nor the cause from the effect. In this way is reiterated the absolute non-evolution of causality. In other words, the knowers of Brahman declare the absence of causality with regard to Ātman.