@snood,
I agree one hundred percent that the motives of northern soldiers are not at issue when the effect was the end of slavery. For that matter, many of them went to war singing John Brown's body:
Old John Brown’s body lies moldering in the grave,
While weep the sons of bondage whom he ventured all to save;
But tho he lost his life while struggling for the slave,
His soul is marching on.
(Chorus)
John Brown was a hero, undaunted, true and brave,
And Kansas knows his valor when he fought her rights to save;
Now, tho the grass grows green above his grave,
His soul is marching on.
(Chorus)
He captured Harper’s Ferry, with his nineteen men so few,
And frightened "Old Virginny" till she trembled thru and thru;
They hung him for a traitor, they themselves the traitor crew,
But his soul is marching on.
(Chorus)
John Brown was John the Baptist of the Christ we are to see,
Christ who of the bondmen shall the Liberator be,
And soon thruout the Sunny South the slaves shall all be free,
For his soul is marching on.
(Chorus)
The conflict that he heralded he looks from heaven to view,
On the army of the Union with its flag red, white and blue.
And heaven shall ring with anthems o’er the deed they mean to do,
For his soul is marching on.
(Chorus)
Ye soldiers of Freedom, then strike, while strike ye may,
The death blow of oppression in a better time and way,
For the dawn of old John Brown has brightened into day,
And his soul is marching on.
(Chorus)
This is one of various versions, almost all of which have the burden of going to war to end slavery as the theme. There are precious few saints and legions of sinners in all such efforts.