Genesis 6:1 says, And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them,  God had intended for people to multiply and populate the earth, and they were doing so.  This does not mean that it was happening in accordance with God's will.  Verse two states, That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose.  Matthew Henry says this means that those men that God had given life to, who should have been as sons to Him, were not guided by God's Spirit when they chose wives.  They simply looked for the women who looked the best.  We cannot be guided simply by physical looks when we are looking for a spouse, but must be guided by the Holy Spirit if we want the best marriage.  Verse three declares, And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.  God was displeased with mankind, but He didn't immediately destroy them.  God gave a warning that people had one hundred and twenty years to repent or they would face destruction.  God is always patient in His grace before He comes to people in judgment.  Still, we can be certain that God's judgment will come.  Verse four says, There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of renown.  Though some attempt to interpret this as some lesser god or angels having children with human wives and creating a race of giants, if we believe God, we know that there are no other gods and that angels are a different form of creation than mankind.  Though people may have looked like giants to those around them, they were still just people.  No matter how big and important people may feel today, they are still simply a part of God's creation and powerless before Him.  Verse five proclaims, And GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.  God saw the wickedness of people, those that were to be the very best of His creation.  As such, God had given them free will.  We today are still the ultimate of God's creation, but we can still choose to ignore or defy Him.  Verse six adds, And it repented the LORD that he had made man on the earth, and it grieved him at his heart.  Mankind had become so evil that God was regretting having created them, and He was grieved because of it.  If we turn away from God continually, He will be grieved at our creation, of the life that He gives us.  Verse six declares, 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.  God said that He was going to destroy not only mankind but all animals as well.  The world was created to follow the laws of God and people were to care for the other animals.  If there were no people, there was no need for the other animals. Unlike people, animals simply live life and pass from existence at death, so this wasn't a harsh sentence for them.  God was not going to act out of anger, but out of disappointment and grief over the actions of people.  Verse eight states, But Noah found grace in the eyes of the LORD.  There was one man, Noah, who was still following God.  Noah found grace in the eyes of God.  We need to be like Noah today, living for God so that He might delay the coming destruction of the world so that others will have a chance to repent and come to God.  Verse nine adds, These are the generations of Noah: Noah was a just man and perfect in his generations, and Noah walked with God.  I don't believe that this means that Noah never sinned, but that he attempted to live by faith in God.  One person walking with God can have a great impact on the world.  Verse ten says, And Noah begat three sons, Shem, Ham, and Japheth.  Noah's sons would be a part of the saving of mankind.