How was the flood in the time of Noah just? How can God be good?
Here's the answer:
God sent the flood because the people were being wicked. God is good and He is just.
God sent the flood during the time of Noah because of the wickedness in the world. God looked upon the earth and saw that everyone was evil except Noah (Genesis 6:5). God is loving, but He is also just. This means that He will not allow wickedness to carry on.
After the flood, God was able to start over with mankind. Even though God destroyed the people, He is still good. Psalm 92:15 says, "They will say to everyone, 'The LORD is honest. He is my Rock, and there is no evil in him.'" There is no wickedness in God—He is 100 percent good.
The flood in the time of Noah was just because all of the people were following after evil. Good didn’t destroy the entire human race. He saved Noah, Noah’s wife, Noah’s three sons, and his son’s wives. Through Noah’s sons and their wives, the earth was repopulated. Through each pair of animals, the animals were repopulated. God is not evil for sending the flood. He was making the world better by destroying those who were following evil.
"The Lord saw how bad the sins of everyone on earth had become. They only thought about evil things" (Genesis 6:5).
"The earth was very sinful in God’s eyes. It was full of people who did mean and harmful things" (Genesis 6:11).
"Every living thing on earth was wiped out. People and animals were destroyed. The creatures that move along the ground and the birds in the sky were wiped out. Everything on earth was destroyed. Only Noah and those with him in the ark were left" (Genesis 7:23).