Question

which scripture proclaims that the jiva that is bound in the prakriti is brahman itself

Answer 1

In Hindu Upanishads, it is mentioned that Jiva and Prakriti together is Brahman itself.

Jiva is a being with life while Prakriti is the nature. The one true God is called Brahman, who has many forms and exists over the universe. In Hinduism, it is believed that every person has a soul which is Brahman and it is called the Atman.

The Samkhya school of Hinduism which is related to the Yoga school of Hinduism refers to Prakriti as nature, which has three Gunas or tendencies viz. creation, preservation and destruction.