DAVID LLOYD GEORGE (SEE BELOW) UNDERSTOOD THE FIRST WORLD WAR IN THE IMAGE OF MEN BEING THROWN INTO A FURNACE, stating that the war was conducted as if there were no limit to the number of men who were fit to be thrown into the furnaces (see what he said directly below). 

Lloyd George had been to the furnace, he said, and witnessed men marching into the furnace.

Hitler fought in the First World War and was aware that millions of men had been immolated in the flames of this war. Please see "What did Hitler do in the First World War." 

It is estimated that at least nine-million men died in the First World War.

In Hitler's mind, however, Jews had escaped immolation in the First World War--by shirking their duty to fight (this was not the case--German Jews died  in the First World War in the same proportion as non-Jewish Germans).

 Hitler was determined that Jews would not escape the immolation he believed they had avoided. They would be immolated in ovens in death camps. If German men had died in the First World War, so Jews would die in the Final Solution. They too would be thrown into a furnace. 

The Holocaust replicated the mass-murder of the First World War. The First World War and Holocaust were two sides of the same coin.

The image below is of men being shoveled into a furnace--depicting what happened in the Second World War. But it is equally a depiction of what happened to the Jews.