Mandukya Karika, verse 4.53

Text

द्रव्यं द्रव्यस्य हेतुः स्यादन्यदन्यस्य चैव हि ।
द्रव्यत्वमन्यभावो वा धर्माणां नोपपद्यते ॥ ५३ ॥

dravyaṃ dravyasya hetuḥ syādanyadanyasya caiva hi |
dravyatvamanyabhāvo vā dharmāṇāṃ nopapadyate || 53 ||

53. Substance may be the cause of another substance. That which is not substance may be the cause of another which is not substance. But the Jīvas (or beings) cannot be possibly anything like substance or other than substance.

Shankara Bhashya (commentary)

It has already been established that the essence of Self is one1 and unborn.2 Those who imagine causal relation in Ātman must admit that substance may be the cause of another substance and that3 which is other than substance may be the cause of something else which is also other than substance. But a thing itself cannot be the cause of itself. Further, we do not find in common experience a non-substance which is independently the cause of something. The selves (i.e., the Jīvas or beings) can be called neither substance4 nor other5 than substance. Hence the Jīvas or selves cannot be the cause or effect of anything. Therefore Ātman, being neither substance nor other than substance, is neither the cause nor the effect of anything.