Transcendence is the goal of the development, but it does not exclude the possession of that which is transcended. The soul need not and should not push transcendence so far as to aim at its own extinction. Nirvana is extinction of the ego-limitations, but not of all possibility of manifestation, since it can be possessed even in the body.
The desire of the exclusive liberation is the last desire that the soul in its expanding knowledge has to abandon; the delusion that it is bound by birth is the last delusion that it has to destroy.
Translation and Commentry Published, Isha Upanishad Analysis, CWSA, Sri Aurobindo.