I was flying back from Chicago a few days ago, and I had the pleasure of sitting next to a geologist/palentologist. I was curious about all the articles he was reading and we got into a very civilized conversation, and I asked some very pointed questions regarding his scientific methods. It turned out that he was very much a worshiper of science and an atheist. I kept the conversation light, curious, and respectful he did the same. Every time I mentioned the Word of God, or what God has done, and will do, he spouted that God contradicts Himself through out a document written by man with no scientific proof.
His one focused contradiction was in Gensis 6:19-21, and 7:2-3. My response to this was that God was giving specific requirements for certain animals clean/unclean. And yet he still says its contradictory.
So my question to you, what is God actually telling Noah to do in regards to the animals to be stored in the Ark?
In Genesis 6:19-21 God told Noah that 2 of every kind of animal would come to him to be saved from the coming flood. In Genesis 7:2-3 He further instructed Noah to take 7 of each kind of clean animal as well as 2 of the unclean ones. Your unbelieving friend sees a contradiction because he wants a reason to doubt. You and I see no contradiction because we understand that God was simply clarifying His instructions so that enough sacrificial animals would be included. Therefore it’s not the statements themselves, but our perception of them that’s different.
As is the case with unbelievers, your friend missed the real question that the comparison between the two passages is meant to raise. And that is, how did Noah know the difference between “clean” and “unclean” animals? The Levitical system was still over 1000 years in the future. The answer is that the idea of innocent blood being shed for the remission of sin had to have been introduced immediately after the fall to protect fallen man from dying in his sins. It was only formalized at Mt. Sinai.