Poetry is notoriously hard to translate effectively in general, and here we have some special difficulties: The diction is archaic even for the 19th century, being much influenced by the King James Bible. More, the images often allude to the Bible, and would require some ingenuity & tact to translate for the benefit of a nonChristian audience. The grapes of wrath would be hard enough, but hardest of all would be the wonderful lines

I have read a fiery gospel, writ in burnished rows of steel:
"As ye deal with my contemners, so with you my grace shall deal;
Let the Hero, born of woman, crush the serpent with his heel...."

The second line alludes to the Golden Rule, the Lord's Prayer, and the parable of the sheep and goats. The third alludes to the temptation in Eden, with the pagan word "hero" daringly (I suppose some would say blasphemously) thrown in to identify the Union soldiers with Christ. Fancy getting all that in without a lecture!