First birth is from your parents, but real birth, real life, begins when one accepts a bona fide spiritual master and renders service unto him. Then the path is open for going back to home, back to Godhead, to live eternally in full knowledge and full bliss and in association with the Supreme Personality of Godhead Himself, Lord Krishna. – In his letter to Narayani, 11th June, 1972.
One cannot calculate the amount of loss there is in wasting valuable time. Either materially or spiritually, one should be very alert in utilizing the time which he has at his disposal.
Srimad Bhagavatam 2.7.15,
Srila Prabhupada
When the soul leaves this body, then what is it? It has no value, a lump of matter, just like a motorcar. So as long as it is moving, it is worth one lake, and as soon as it does not move, it is simply a lump of iron and copper and something. Who cares for it? It is thrown away. Same thing. The body has no value. It has value as long as the soul is there.