BG Chap 13 - The purpose of the field
The body is a transformation of the elements and supports the jīva in his quest for enjoyment or liberation. The living being is limited by the interactions of his body, mind and karma, which constitute his field of activities. Every living entity’s kṣetra is arranged by his karma, through the agency of māyā. Kṛṣṇa therefore is not partial, because as the Supersoul, the knower of all kṣetras, He simply sanctions the awarding of each living entity’s field of activities. The body is also the svarūpa of the field. Thus the field endowed with transformations of birth, growth, maintenance, maturity, dwindling and death has been briefly described.