Acharya Prashant explains the concept of 'Yagya' as the act of elevating resources from a lower level to a higher, supreme purpose. Using the analogy of oil, he describes how it can remain unused, be misused, or be offered to a lamp to become light; the latter represents Yagya. He defines 'Avashishta' not as something saved for personal gain, but as the residue that is unfit for the sacred fire. He emphasizes that resources like time, money, energy, and labor should be redirected from trivial pursuits to higher goals, such as education or spiritual growth. He clarifies that Yagya is not about self-sacrifice for others in a worldly sense, but about recognizing that the individual and the whole are one; thus, serving the 'root' or the source ultimately benefits the individual, much like a leaf giving water to the roots of a tree.