The most expensive in humans - this is life. It gives him the once, and it must be to live in such a way that was not painfully hurt for aimlessly lived years in order not to disgrace zheg for podlenkoe and mercantile past and that, dying, has been able to say: the whole life and all forces were given the most beautiful in the world - the struggle for the liberation of humanity. "

Man's dearest possession is life . It is given to him but once, and he must live it so as to feel no torturing regrets for wasted years, never know the burning shame of a mean and petty past; so live that, dying, he might say: all my life , all my strength were given to the finest cause in all the world——the fight for the Liberation of Mankind.

--Ostrovsky

The complete paragraph is:

The most precious thing for a person is life. Everyone has only one life. A person's life should be spent like this: looking back on the past, he will not regret for wasting his life, nor will he be ashamed of living a mediocre life; when he is dying, , he could say: My whole life and all my energy are dedicated to the most magnificent cause in the world - the struggle for the liberation of all mankind.

--Ostrowski