Black Sabbath's War Pigs first appeared on their album "Paranoid".  Based on the laziness of politicians who sit back while others fight their war, War Pigs is one of their greatest protest songs.

Generals gathered in their masses,
Just like witches at black masses
Evil minds that plot destruction,

Sorcerer of death's construction
In the fields the bodies burning,
As the war machine keeps turning
Death and hatred to mankind,
Poisoning their brainwashed minds
Oh Lord Yeah!

Politicians hide themselves away
They only started the war
Why should they go out to fight?
They leave their role to the poor, yeah

Time will tell on their power minds,
Making war just for fun
Treating people just like pawns in chess,
Wait 'till their judgement day comes, yeah

Now in darkness world stops turning,
Ashes where the bodies burning
No more War Pigs have the power,
Hand of God has struck the hour
Day of judgement, God is calling
On their knees the war pigs crawling,
Begging mercy for their sins
Satan, laughing, spreads his wings
Oh Lord Yeah!

"Walpurgis" Lyrics:

Witches gather at black masses
Bodies burning in red ashes
On the hill the church in ruin
Is the scene of evil doings
It's a place for all bad sinners
Watch them eating dead rats' innards
I guess it's the same whereever you may go
Oh Lord yeah

Carry banners which denounce the lord
See me rocking in my grave
See them anoint my head with dead rat's blood
See them stick the stake through me
Oh

Don't hold me back cause I've just gotta go
They've got a hold of my soul now
Lords got my brain instinct with blood obscene (not sure about this line)
Look in my eyes I'm there enough
Yeah

On the scene a priest appears
Sinners falling at his knees
Satan sends out funeral pyre
Casts the priest into the fire
It's the place for all bad sinners
Watch them eating dead rats' innards
I guess it's the same whereever you may go
Oh lord yeah