What is there better to choose from than the closing lines of Tennyson's Ulysses, whose words I love:

Come, my friends,

`Tis not too late to seek a newer world.

Push off, and sitting well in order smite

The sounding furrows; for my purpose holds

To sail beyond the sunset, and the baths

Of all the western stars, until I die.

It may be that the gulfs will wash us down:

It may be we shall touch the Happy Isles,

And see the great Achilles, whom we knew.

Tho` much is taken, much abides; and tho`

We are not now that strength which in old days

Moved earth and heaven, that which we are, we are;

One equal temper of heroic hearts,

Made weak by time and fate, but strong in will

To strive, to seek, to find, and not to yield.