I didn't know that so I Googled & found it:
O steep and rugged Life, whose harsh ascent
Slopes blindly upward through the bitter night!
They say that on thy summit, high in light,
Sweet rest awaits the climber, travel-spent;
But I, alas, with dusty garments rent,
With fainting heart and failing limbs and sight,
Can see no glimmer of the shining height,
And vainly list, with body forward bent,
To catch athwart the gloom one wandering note
Of those glad anthems which (they say) are sung
When one emerges from the mists below:
But though, O Life, thy summit be remote
And all thy stony path with darkness hung,
Yet ever upward throught the night I go.
Thanks verbiphobe