Rainbow is the sign of the covenant between God and the earth

Genesis 9:1-29
Be fruitful and increase in number and fill the earth, which is the role of human being in the earth.
Whoever sheds human blood, by humans shall their blood be shed; for in the image of God has God made mankind. God's judgement.
God established his covenant with Noah and with Noah's descendants. Never again will all life be destroyed by the waters of a flood; never again will there be a flood to destroy the earth. God set rainbow in the clouds, and it will be the sign of the covenant between God and the earth.
Noah has three sons, Noah cursed Canaan for he save Noah's naked!  The lowest of slaves will he be to his brothers.” He also said, “Praise be to the Lord, the God of Shem! May Canaan be the slave of Shem" May God extend Papheth’s territory.
Why?
God hope human could be numerous, for God loves man.
Hand by hand, tooth by tooth. God wants people respect other's life. Respect other is honor the name of God.
Rainbow is symbol of covenant between God and the earth. There is not flood to destroy the earth anymore, but there will be fire to punish sinners on the earth.
How?
Rainbow, how beautiful it is, remember it is the covenant of God's love and judgement.