Black Sabbath really rhymed "masses" with "masses". I always thought they were saying "messes" as in a military officer's mess hall, but no, after further research I think they're really saying "masses" twice.
This song sticks out to me, it's timeless, as we see by all the different covers. CAKE's cover owns it their signature dull monotone. T-Pain is my favorite tho, he gives it a kinda psychedelic rock sound.
Also, the song alludes to two groups of elites, the generals, who orchestrate the horror, and the politicians who started it. Imo tho the "War Pigs" could be an allusion to anyone who profits from the war, whether from a salary, a lobby, or literal financial profits. They're pigs, and we all know who's traditionally portrayed as pigs 
Anyways, here's links to all three versions
Is it just me or is he singing "gathered" down a semitone in the CAKE cover. It might be artistic license but it cooks my brain every time