In verse 11 God again reminds us of the corruption that permeated the earth at the time of Noah. The corruption included violence. When the fear of God is missing, it stands to reason that violence will be the norm. People will lack any sense of reasonableness. Their actions will be irrational and disastrous for all involved. God protected Noah and his family during this extremely violent time.
In verse 12 we read further of God’s assessment of the situation on earth. It is God’s assessment that matters. Ungodly people tend to adjust to wickedness and they tend to accept it as the new normal. When we look at Canada today and compare that to the Canada of 70 years ago, the changes are quite drastic. The changes have not been for the better. Things are much worse now than they were then. The wicked would maybe notice some of that, but they would just adjust and accept it. The few who are saved, would note the changes and would not accept it. They would seek to help the lost to see the need to repent and know the true God. Active and true evangelism is the work of the people of God. We have more opportunities of reaching the lost today than 70 years ago. We can now broadcast via the internet and for a fraction of the cost of broadcasting via radio just a few decades ago.
In verse 13 the LORD communicated His concerns to Noah. God was not going to allow the violence of that time to continue unchecked. He was going to destroy all but Noah’s immediate family. He would start over again with just 8 people.
In verse 14 God began to instruct Noah as to His way of saving him and his family. Noah could not just sit around and watch God do it all. God taught Noah that he needed to do something in order to protect himself. This again would not involve works salvation. We have already noted that God declared Noah to be just and perfect and walking with the LORD. Noah’s relationship with the LORD was already established. His actions would prove his right relationship with the LORD.
God began by telling Noah what he was to build and with what he was to build. He was to use gopher wood to build an ark. This was something new for Noah. He had never built such a thing in the past. God is all wise and He would give Noah detailed instructions and since man was created with intelligence, Noah would be able to follow the instructions given to him.
The issue for Noah was the same as for any person. It is never that God has made it too difficult for man to follow Him. It is always about man’s willingness to submit to God’s authority. Adam chose not to submit to God’s will. Cain chose not to submit to God’s will. Noah chose to submit to God’s will. Noah was blessed because he chose to submit to God’s will.
In verse 15 God gave Noah the overall details of the ark. God gave him a mental picture of what he was going to build. We do not measure things in cubits today. The standard understanding of the cubit in the Bible is 18”. Using that standard, the ark would be 450 feet long and the breadth would be 75 feet and the height would be 45 feet. This was not some small canoe. It was a massive ship that would have been unique for that time. Studies have been done on the measurements of this ark and they have concluded that this ship was the perfect design for safety and longevity. This should not be surprising since God gave the instructions for this ark.
In verse 16 further details of the ark were given. It would have 1 door and 1 window, and it would have 3 stories. Noah needed some specific skills in order to build this ark. He would need to know how to build things in a manner that they could withstand the movement of the ark in the water. Noah would not be building from experience. He had never built anything like this before. He also would not have opportunity to make any adjustments to this structure. He needed to build it with precision and he needed to build it right the first time. He could trust the blueprints. He could trust his abilities. God was in charge. He was trusting God. He knew he could do what God wanted, because he walked with God. Noah did not have all the Biblical record that we have. He had all he needed to trust God. God had already revealed His greatness with Creation. Again we know that the problem for man is not a lack of proof of God’s goodness and greatness. The problem is the heart of man.
Noah had his heart changed by God and he was willing to listen to God’s Word.
As we move on, we will see that the ark is a picture of God’s salvation. God’s salvation is for all people. It is unique. It is clearly visible for all to see. The problem is:

II Corinthians 4:3 But if our gospel be hid, it is hid to them that are lost:
4 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.
5 For we preach not ourselves, but Christ Jesus the Lord; and ourselves your servants for Jesus' sake.
6 For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ.