Design
श्रीभगवानुवाच |
अक्षरं ब्रह्म परमं स्वभावोऽध्यात्ममुच्यते |
भूतभावोद्भवकरो विसर्ग कर्मसञ्ज्ञित || 3||
Design

8.3
The Lord said The Supreme Indestructible Entity is called Brahman; one’s own self is called
adhyatma
. Actions pertaining to the material personality of living beings, and its development are called karma, or fruitive activities.

The Vedas address God by several names; Brahman is one of them. In this verse, Shree Krishna says to Arjun that the Supreme Entity is called the Brahman. Time, space, the chain of cause and effect, etc., are all characteristics of the material realm. However, the Brahman is beyond these, as He is transcendental to the material plane. He is described as
aksharam
or indestructible because He is unaffected by the changes in the universe.
The Brihadaranyak Upanishad 3.8.8 states, “Learned people speak of Brahman as
akshar
(indestructible).  It is also designated as
Param
(Supreme) because It possesses qualities beyond those possessed by maya and the souls.”
The word
adhyatma
has two meanings in Sanskrit. One is the science of the soul, and the second is the path to spirituality. However, here Shree Krishna has used it for one’s own self that includes the body, mind, and intellect.
Karmas are fruitive activities performed by a person. It is these karmas that forge every individual’s distinct conditions of existence in various lifetimes. They keep the soul circling in samsara or the cycle of material existence.