Explanation:
In the Gita, only two entities are mentioned. One is the gross body (deha) and the other is the jivaatman (dehi), which is the composite of jiva and Atman. Atman is general awareness and jiva is specific awareness. If this sub-division is neglected, both Atman and jiva stand as only one entity, which was referred to as dehi in the Gita. In that case, there are only two bodies viz. the external gross body (deha) and the internal jivaatman (dehi).
Note:
Atman and jiva both together are called as dehi, in the second chapter of the Gita in the beginning itself. Only two entities are recognized, body and soul. Soul is considered here as the causal body and subtle body taken together. The three bodies are not mentioned in the Gita. This is because the two bodies (subtle and causal) put together, are treated as one body. The casual body is like standstill water and the jiva is the bundle of waves. There is no wave without water. Therefore, the two cannot be isolated or separated; the two together are treated as one entity.
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