This text comes from Wessex Poems and Other Verses, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
THREE captains went to Indian wars,
And only one returned:
Their mate of yore, he singly wore
The laurels all had earned.
At home he sought the ancient aisle
Wherein, untrumped of fame,
The three had sat in pupilage,
And each had carved his name.
The names, rough-hewn, of equal size,
Stood on the panel still;
Unequal since.—“'Twas theirs to aim,
Mine was it to fulfil!"
—"Who saves his life shall lose it, friends!"
Outspake the preacher then,
Unweeting he his listener, who
Looked at the names again.
That he had come and they'd been stayed,
'Twas but the chance of war:
Another chance, and they'd sat here,
And he had lain afar.
Yet saw he something in the lives
Of those who'd ceased to live
That rounded them with majesty
Which living failed to give.
Transcendent triumph in return
No longer lit his brain;
Transcendence rayed the distant urn
Where slept the fallen twain.