There are 2 passages in the Vairocana Sutra, which talks about the Great Self – to the point that even our very own Buddha’s lineage – Sakyamuni Buddha’s lineage – is called the lineage of the Great Self. So this is a primary source text.
So isn’t it interesting that Buddhism today keeps talking about how the Buddha’s teaching is the teaching of “no self”?
This is why it’s so important for us to read the original Sutras and Suttas for ourselves, rather than merely rely on modern day books and websites because often, they are more interpretations rather than source material.
Here are the passages from the Vairocana Sutra:
These are called the “Five Great Crowns” and [belong to] Sakyamuni’s lineage of the Great Self…
If someone who has obtained initiation into the Great Vehicle in the mandala “Born of Compassion”, is adaptable and well behaved, and is always compassionate and benefits others – views Bodhi as an objective entity, he will never be able to see it.
[But] if he is able to recognize this Great Self in his inner heart, [He will find that] the place in which the [mantra] guide resides conforms with the station of his own heart.
Source: The Vairocanabhisambodhi Sutra, Translated from the Chinese (Taisho Vol 18, No. 848) by Rolf W. Giebel. Numata Center for Buddhist Translation and Research 2005. p32, 175, 176.