首楞嚴義疏注經 9.164

9.164

一真妙體本無二相，前文云「我與如來真妙淨心無二圓滿。」斯則心、佛、眾生三無差別也。

The single real, wondrous essence fundamentally has no dual characteristics. The earlier text states: 'The true, wondrous, pure mind of myself and the Tathāgata is non-dual and complete.' This is indeed that mind, Buddha, and sentient beings—these three are without distinction.