When God created man, He knew they would sin because of free will. Why then did He, the God of peace and love, kill almost everyone in the Great Flood? If He knew they would sin, it seems to me that He 'threw a fit' and killed everyone (minus Noah, etc.). That seems far from perfection to me. Am I missing a key teaching about this that explains His actions outside of the free will concept?
Your questions are very good and common ones. I struggled with these issues myself as a lot of us do. You asked about the events pertaining to the flood in Noah's day and also how God's wrath relates to our free will. I will try to answer both of these questions separately as I think there is a clear distinction between God's sovereign right and judgment and our free will that has to be understood.
First, pertaining to the destruction of mankind in the flood of Noah. It is hard for us to understand that the world could have been in such a state that God decided to wipe out everything and everyone. No God did not have a 'fit' as you put it. Noah warned all of the people as God told him to do. God's judgment is right and righteous. I could answer you by saying, its His world, He can do what ever He wants as some would answer this and even though that is correct, we need to understand, and accept that His decisions are the right decisions even if they make no sense to us and may "seem to be far from perfection" as you also stated. Throughout biblical history, God continuously gave the people a chance to repent, but our free will decided otherwise. To answer this question about God's decision to destroy everyone, The book of Genesis gives us a clue as to why the decision was made;
“Then the LORD saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. And the LORD was sorry that He had made man on the earth, and He was grieved in His heart. So the LORD said, “I will destroy man whom I have created from the face of the earth, both man and beast, creeping thing and birds of the air, for I am sorry that I have made them.” But Noah found grace in the eyes of the LORD.” Gen 6:5-8
There is a key part of the verses above; "that every intent of the thoughts of his heart was only evil continually. " The only conclusion we can make from this is that the world had to be so corrupt, enough that God decided it just wasn't going to work and that His decision to destroy everyone was the right thing to do.
Here lies the difficulty. How can we make sense that destroying people because He didn't like the way things were going be just? Even more, how can we just take at face value that all of His decisions are right? Well ask yourself how I, a limited finite being can fully understand an unlimited infinite creator? Our faith is not a blind faith. It is a belief that God is true and righteous. Abraham was a prime example. He was about to kill his only son that he loved more than anything. He would have gone through with it because he believed God’s decisions and commands were just. His faith in God is a true testament of how we should believe in God.
To look at it from another angle, we need to have moral standards pertaining to our lives that originate from outside the corrupt lives we live or they can never be moral. We can not be the ones who create and do evil and also be the ones who define what is right and not evil. These standards have to come from God, and if we believe that His standards are true and righteous, then we should have the same confidence that His decisions pertaining to anything are just, righteous and true also. If not, then everything becomes what is known as subjectivism (meaning, you think this particular thing is ok, but the another person thinks it’s wrong etc.). So with that, we can be confident that His decision to destroy everything was the right thing to do.
Secondly, you asked about our free will especially since God knows we will sin? Again, a tough concept to understand. Yes, God does know all. Yes, He knows we will sin. However if 'free will' is to be truly free will, then it has to be just that- free for us to decide to sin or not. if it were not that way, we would be programmed robots, doing everything He has decided for us to do and that would certainly not be free will. I don't know about you, but if I had the ability to create people, I'd want them to come to me because they decided to love me by their own decision.
These things are very tough for us to understand. I can only add, it is important to not just look at what appears to be bad in scripture, but look at the good. If everyone would adhere to the ten commandments, then none of this would be an issue. Can you imagine how life would be? It will be that way eventually with the second coming of our Lord. God knew this and this is why it was His plan form the very beginning to give us a savior. To give us an alternative to our ‘ free will’ decision to sin- Himself, through Jesus Christ.
I hope this helps. Also, understand none of us can truly comprehend why God does or does not do the things He does, just keep your faith, and believe that His decisions are the right ones. If you don't, who or what else do you have to rely on ?