The Encyclopaedia Britannica has this to say of Longfellow --
During his lifetime Longfellow was loved and admired both at home and abroad. In 1884 he was honoured by the placing of a memorial bust in Poets' Corner of Westminster Abbey in London, the first American to be so recognized. Sweetness, gentleness, simplicity, and a romantic vision shaded by melancholy are the characteristic features of Longfellow's poetry. He possessed great metrical skill, but he failed to capture the American spirit like his great contemporary Walt Whitman, and his work generally lacks emotional depth and imaginative power. Some years after Longfellow's death a violent reaction set in against his verse as critics dismissed his conventional high-minded sentiments and the gentle strain of Romanticism that he had made so popular. This harsh critical assessment, which tried to reduce him to the status of a mere hearthside rhymer, was perhaps as unbalanced as the adulation he had received during his lifetime. Some of Longfellow's sonnets and other lyrics are still among the finest in American poetry, and Hiawatha, "The Wreck of the Hesperus," Evangeline, and "Paul Revere's Ride" have become inseparable parts of the American heritage. Longfellow's immense popularity helped raise the status of poetry in his country, and he played an important part in bringing European cultural traditions to American audiences.
Today's poem titled A Psalm of Life was interestingly also titled (by Longfellow himself) A Psalm of Death, before Longfellow decidedly changed the title to meet the optimistic sentiment he gushes forth in the poem.
A Psalm of Life
What the heart of the young man said to the psalmist
Tell me not, in mournful numbers,
Life is but an empty dream! --
For the soul is dead that slumbers,
And things are not what they seem.
Life is real! Life is earnest!
And the grave is not its goal;
Dust thou art, to dust returnest,
Was not spoken of the soul.
Not enjoyment, and not sorrow,
Is our destined end or way;
But to act, that each to-morrow
Find us farther than to-day.
Art is long, and Time is fleeting,
And our hearts, though stout and brave,
Still, like muffled drums, are beating
Funeral marches to the grave.
In the world's broad field of battle,
In the bivouac of Life,
Be not like dumb, driven cattle!
Be a hero in the strife!
Trust no Future, howe'er pleasant!
Let the dead Past bury its dead!
Act, -- act in the living Present!
Heart within, and God o'erhead!
Lives of great men all remind us
We can make our lives sublime,
And, departing, leave behind us
Footprints on the sands of time;
Footprints, that perhaps another,
Sailing o'er life's solemn main,
A forlorn and shipwrecked brother,
Seeing, shall take heart again.
Let us, then, be up and doing,
With a heart for any fate;
Still achieving, still pursuing,
Learn to labor and to wait.
-- Henry Wadsworth Longfellow
In one of the early stanzas Longfellow urges the reader to "Be not like dumb driven cattle, Be a hero in the strife". I think, and history stands in evidence and judgement, that any mass or gathering of people collectively does not think. Only individuals think. Masses have strength and can execute extraordinary tasks. But thinking stays the prerogative of the individual. Situation not withstanding. One can conceive extreme examples in Hitler or Advani as the individual and the Gestapo or Kar-Sevaks and other following as the masses; to a handful of researchers as the individual, and a large company as the mass, which can execute and build real products like computers, space ships, etc. I think Longfellow understood this and therefore exhorts his fellowmen to be thinking individuals, to be heroes in strife and not be like dumb driven cattle.
Of course, some memorable phrases like Footprints on the sands of Time and entire stanzas on Trust no future, Dead past bury its dead, Heart for any strife, Learn to labor and to wait -- the simple elegance with which Longfellow puts forth fairly well thought out concepts with astonishing ease, make this a much loved poem.