But that's all scene setting. The real story is that God has gone in a massive strop with mankind and decided to drown all living things in a massive flood. He makes it sound like he regretted creation completely:
6:7 And the LORD said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repenteth me that I have made them.
However, he's just about to order Noah (whose ways are "perfect") to build an ark so that human and animal life may continue. I don't get it.
Anyway, in chapter six the big G tells Noah to take two of every animal onto the ark in order that life on Earth may continue. BUT WAIT! In chapter seven he orders Noah to take seven of every "clean" animal and of every fowl and two of every "unclean" animal. Then, later in chapter seven Noah takes two of every clean animal, two of every fowl and two of every unclean animal. Confused dot com.
I'm starting to become suspicious that two or more versions of roughly the same story have been taped together here, making a kind of Frankenstein's monster of a tale. Seems like a reasonable way to explain both this and the two accounts of creation.
After the cull of all living things (fish? they're not mentioned, were they spared?) Noah sends out a dove to check that the flood waters have abated, which they have not. So he waits seven days before sending out the dove again, which this time returns with an olive leaf. Where from, you might well wonder. The Earth has been under a flood that covered even the highest mountains for the best part of a year.
So, in thanks for being spared from the deluge, Noah kills and burns one of every clean animal and one of every fowl (this is often thought of as a problem, but I guess the animals could have reproduced during the many months they were on the ark - it's certainly not the most ridiculous aspect of the tale). The sacrifice pleases God, and, now that he's chilled out a bit, he decides that it's not really man's fault that he's evil, he's that way from birth (presumably God's fault then? And how did this escape his infinite wisdom earlier?).
So he promises never to kill everything ever again. Phew.
And we all live happily ever after.
Or do we?
I suspect not.