Brahma Sutras 1.20

अन्तस्तद्धर्मोपदेशात् ॥

antas tad-dharma-upadeshat

The being within is Brahman, because the qualities of Brahman are taught.

[हृदय के] भीतर [जो है, वह ब्रह्म है] क्योंकि उसके धर्म (गुण/लक्षण) का उपदेश है ॥