I think the verses may be a parody of a hymn -- just a guess. The tune as a whole sounds hymn-like, and the phrase "we're coming, we're coming, our brave little band" especially so.

The only occurrence of "we're coming, we're coming" I've been able to turn up occurs in the following 1844 anti-slavery hymn. The meter scans right -- but I can't find the melody "Kinloch of Kinloch" in my (admittedly limited} tune sources. Can anyone help? There's a slim chance it might be the tune to "Away With Rum!"

WE'RE COMING! WE'RE COMING.

AIR--Kinloch of Kinloch. From Geo. W. Clark, The Liberty Minstrel, 1844 (an anti-slavery songbook).

We're coming, we're coming, the fearless and free,
Like the winds of the desert, the waves of the sea!
True sons of brave sires who battled of yore,
When England's proud lion ran wild on our shore!
We're coming, we're coming, from mountain and glen,
With hearts to do battle for freedom again;
Oppression is trembling as trembled before
The slavery which fled from our fathers of yore.

We're coming, we're coming, with banners unfurled,
Our motto is FREEDOM, our country the world;
Our watchword is LIBERTY--tyrants beware!
For the liberty army will bring you despair!
We're coming, we're coming, we'll come from afar,
Our standard we'll nail to humanity's car;
With shoutings we'll raise it, in triumph to wave,
A trophy of conquest, or shroud for the brave.

Then arouse ye, brave hearts, to the rescue come on!
The man-stealing army we'll surely put down;
They are crushing their millions, but soon they must yield,
For _freemen_ have _risen_ and taken the field.
Then arouse ye! arouse ye! the fearless and free,
Like the winds of the desert, the waves of the sea;
Let the north, west, and east, to the sea-beaten shore,
_Resound_ with a _liberty triumph_ once more.

(By the way, Dave Braham's tune to "Salvation Army" is a modest rework of an Irish dance tune ... can't think of the title, but anyone who wants can check the Levy Collection sheet music for "Salvation Army" and see if you can identify it. It partly resembles the Brigger tune for "Away With Rum" but there are lots of differences too.)