Second, 6:5,11,12 describes an almost total moral corruption of the human race (notice the superlatives in 6:5), and the extreme and pervasive violence and ecological damage that resulted. Imagine a world in which only totally hardened Lamech's/Hitler's lived for hundreds of years! Imagine a world like "Road Warriors" on steroids! God is not stepping into to ruin a pristine world; He is rescuing it from total destruction. God did not abandon His plan to redeem humans through Eve's seed; He started over so that His plan could proceed.
One more point before we move on. The fact that God was grieved by the corruption of the human race (6:5-7) speaks of God's personal nature and compassion – not of His ignorance that this would happen. If we are often grieved by events we knew would happen, how much more is God grieved?
So God intervened to rescue the human race from total corruption. He judged His enemies through a cataclysmic deluge, and He provided an ark to deliver His followers from this judgment. While this event obviously had great significance for those who experienced it, the New Testament (which constantly affirms the historicity of Noah and the deluge) tells us that it also foreshadowed even more significant future events and illustrated even more significant truths . . .
Lessons from the New Testament
When Jesus was asked about His future return at the end of the age, He responded by referring to the deluge during Noah's lifetime (read Matt. 24:37-41). Jesus' point is His return will take people by surprise because of their culpable ignorance. They were warned (by Noah's ark-building and preaching – more later), but they rejected the warnings ("Nothing like this has happened before!") and went on obliviously – until the flood came and carried them all away.
Despite centuries of warning of Jesus' return,Noah and his family were rescued from the deluge by God's appointed means – inclusion into the ark. They had to choose to believe God's word and enter inside the ark, trusting God to close the door at the proper time (7:16).
Peter says this foreshadows how we are rescued from God's final judgment – by inclusion into Christ (read 1 Pet. 3:18-21). Our baptism is the antitype (antitupos) of the salvation of Noah and his family. "Baptism" means "being put into" (e.g., ships sinking into the sea; cloths immersed into dye). The "baptism" to which Peter refers is not the ritual of water baptism ("not the removal of dirt from the flesh"), but being put into Christ by entrusting ourselves to Him as our Savior ("an appeal to God from a good conscience through the resurrection of Jesus Christ;" see also Col. 2:12). You have heard this good news of God's offer to save you from His judgment through Jesus' death and resurrection. Will you choose to entrust yourself to His promise? At that moment, He will put you into Christ where you will be forever safe! Have you made this choice?
Noah was a preacher of righteousness (2 Pet. 2:5) – he communicated God's warning and (presumably) urged people to join him and his family in trusting God's promise. He may have been doing this before God called him to build the ark (like Seth/Enosh – Gen. 4:26). Certainly he would have done this as people saw him building the ark. His lifestyle (how his time and money was spent) was consistent with his message, and this would have precipitated many interchanges about his faith. Noah wasn't some kind of spiritual survivalist, concerned only about himself and his immediate family. He was also concerned for the others, including those who mocked him. Tragically, none of them responded to his preaching.
So we are to live lifestyles that are consistent with our message. How we spend our time and money ought to reflect what we say we believe about God's coming kingdom. The watching world may conclude that we are crazy, but they should not be able to conclude that we are hypocrites who actually hold to the same (personal peace and affluence) values that they do. Nor should we be Christian survivalists, retreating into our own bunkers until the end of the world comes. Rather, like Noah, we should communicate God's judgment and salvation to people (even those who mock us) – with sincerity and genuine compassion (read 1 Pet. 3:14,15). Hopefully, many will respond to our message – but we must be faithful even if they do not respond!