Verse 20
A new beginning (8:20-9:7)
On returning to the earth now cleansed from sin, Noah first offered sacrifices to God. God's promise not to destroy the earth by a flood again was not because he expected people to improve. He knew they would be as sinful as ever. If God always dealt with people as they deserved, such floods would occur constantly. But in his mercy God would allow sinful people to continue to live on his earth (20-22).
With this new beginning, God gave Noah the same sorts of commands as he had given Adam. People were still God's representatives over the earth, but they still did not have the right to act independently of God. Even in killing an animal for food, they had to realize that they had no independent right to take its life. By not using the animal's blood (representing its life) for their own benefit, they acknowledged that God was the true owner of that life. Human life was even more precious to God than animal life, because human beings were made in God's image. Therefore, any person who killed another without God's approval was no longer worthy to enjoy God's gift of life and had to be put to death (9:1-7).
Verses 8-17
God's covenant with Noah (9:8-17)
A covenant was an agreement between two parties that carried with it obligations and possibly benefits or punishments, depending on whether a person kept or broke the covenant. Covenants to which God was a party, however, differed from covenants between people in that they were not agreements between equals. God was always the giver and the other person the receiver. The covenant promises originated in the grace of God and were guaranteed solely by him.
Earlier God had made a covenant promise to Noah to save him and his family (see 6:18). After the flood God made another covenant promise, and, like the first, it originated entirely in God's grace. The covenant was made not with Noah as an individual but with all earthly life through him. God would never again destroy earthly life by a flood (8-11). God pointed Noah to the rainbow as his sign to all generations that the covenant depended entirely upon him for its fulfilment (12-17).
Verses 18-29
Noah and his sons (9:18-29)
On one occasion Noah brought shame upon himself through becoming drunk. But God's condemnation was concerned more with Noah's son Ham, and particularly his grandson Canaan who tried to add to Noah's disgrace (18-23). God announced a curse on the descendants of Ham who would come through Canaan, though not on Ham's other descendants. The descendants of Canaan would have their land taken from them by the descendants of Shem (the nation Israel) and they themselves would be made to serve Israel (24-26; see Joshua 9:23; Judges 1:28; 1 Kings 9:21).
The descendants of Japheth, who spread to the north and west through Asia Minor and Greece, were promised a share in the blessings of Shem. This was fulfilled when the New Testament church spread through this region and multitudes of Gentiles believed. As a result they enjoyed the blessings of God's people that formerly had been limited largely to Israelites (27-29; see Galatians 3:14; Ephesians 3:6).