Revelation, nothing. The entire Bible is basically God telling the Israelites to stop worshipping Moloch and fucking their sisters, and they fucking them up when they ignore him. I basically read the New Testament as God throwing up His hands and saying "I'm sick of you fucktards, literally any other people are acceptable to me so long as they're not actively disgusting".

The best evidence in support of the Holocaust happening is that it's totally something God would do to the jews for being terrible.