Sri Aurobindo expands on the cryptic descriptions in the Isha Upanishad which seek to provide balance to a one-sided approach to the questions central to our seeking. In this regard, he describes the two realisations that together allow the integration of both timelessness and time without raising irreconcilable contradictions.
“The realisation of timeless immortality comes by the knowledge of self in the Non-birth and Non-becoming and of the changeless spirit within us: the realisation of time-immortality comes by the knowledge of self in the birth and Becoming and is translated into a sense of the persistent identity of the soul through all changes of mind and life and body; this too is not a mere survival, it is a timelessness translated into the Time manifestation. By the first realisation we become free from obscuring subjection to the chain of birth and death, that supreme object of so many Indian disciplines; by the second realisation added to the first we are able to possess freely, with right knowledge, without ignorance, without bondage by the chain of our actions, the experiences of the spirit in its successions of time-eternity. A realisation of timeless existence by itself might not include the truth of that experience of persistent self in eternal Time; a realisation of survival of death by itself might still give room for a beginning or end to our existence. But, in either realisation truly envisaged as side and other side of one truth, to exist consciously in eternity and not in the bondage of the hour and the succession of the moments is the substance of the change…”
Sri Aurobindo, The Life Divine, Book 2, Part 2, Chapter 19, “Out of the Sevenfold Ignorance towards the Sevenfold Knowledge.”