Soul
Bhagvadgita Chapter 2 Verse 13:
dehinosmin yataa dehe
kaumaaram yavanam jara
tatha dehaantara praptir
dheeras tatra na muhyati
Just as the body passes from childhood, youth to oldage; the soul passes from one body to take up another new one at death. This is the reason realized person will not bewilder due to this.
Bhagvadgita Chapter 2 Verse 20:
na jaayate mruthyate vaa kadaachin
naayam bhoothva bhavitha vaa na bhuyah
ajo nityaha shasvato yam puraano
na hanyate hanyamaane sharire
There is no birth or death to a soul. There has been no time when soul wasn't present. There will be no time when it will cease to exist. The soul is eternal, unborn and primaeval.