देहिनोऽस्मिन्यथा देहे कौमारं यौवनं जरा।
तथा देहान्तरप्राप्तिर्धीरस्तत्र न मुह्यति।।2.13।।
As are boyhood, youth and decrepitude to an embodied being in this (present) body, similar is the acisition of another body. This being so, an intelligent person does not get deluded.
Now, Atman is eternal like what. In order to give analogy, Bhagvan says-
Dehi is that to whom this body belongs. That is atman. Now just as in this body there are three distinct states of childhood, youth and old age and that there is no change in atman while the body crosses these states, similarly this atman, being transformation-less, does not change while there is a change in body. The wise therefore do not get deluded by this.
The one, who knows the atman in this manner, cannot have that moha which is the destroyer of atman. However, they too are generally seen to go through sukha and dukha caused by cold and warmth etc—- and subsequently through the moha– caused by dissociation from sukha, and shoka—caused by association of dukha. Anticipating such objection from Arjuna, Bhagvan says—[in next shloka]