This text comes from The Complete Poems of Paul Laurence Dunbar, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
I've a humble little motto
That is homely, though it's true,—
Keep a-pluggin' away.
It's a thing when I've an object
That I always try to do,—
Keep a-pluggin' away.
When you've rising storms to quell,
When opposing waters swell,
It will never fail to tell,—
Keep a-pluggin' away.
If the hills are high before
And the paths are hard to climb,
Keep a-pluggin' away.
And remember that successes
Come to him who bides his time,—
Keep a-pluggin' away.
From the greatest to the least,
None are from the rule released.
Be thou toiler, poet, priest,
Keep a-pluggin' away.
Delve away beneath the surface,
There is treasure farther down,—
Keep a-pluggin' away.
Let the rain come down in torrents,
Let the threat'ning heavens frown,
Keep a-pluggin' away.
When the clouds have rolled away,
There will come a brighter day
All your labor to repay,—
Keep a-pluggin' away.
There'll be lots of sneers to swallow,
There'll be lots of pain to bear,—
Keep a-pluggin' away.
If you've got your eye on heaven,
Some bright day you'll wake up there,—
Keep a-pluggin' away.
Perseverance still is king;
Time its sure reward will bring;
Work and wait unwearying,—
Keep a-pluggin' away.