…Noah, a herald of righteousness…2 Peter 2:5 ESV
What did Noah proclaim? Would he not proclaim what God told him?
“For behold, I will bring a flood of waters upon the earth to destroy all flesh in which is the breath of life under heaven. Everything that is on the earth shall die. Genesis 6:17 ESV
God certainly told Noah more than this, but this word is the heart of the building of the Ark.
The context was a time in which mankind lived upward of 900 years. A little research on your part will reveal that the population was probably between many-hundreds-of-millions to possibly billions of people. A little more research on your part will indicate that we are genetic mutants compared to the people of this time.
Such people would not have stayed in one local area. Even if compelled by some great post-flood patriotism (Genesis 11:4) there would be rebels and outcasts who would leave the ‘local area’ far behind. They, in turn, would multiply and fill the earth.
How would those who heard the preaching of Noah interpret it?
Then, like now, there would be apostates who proclaimed their faithfulness to the Creator and yet doubted Noah’s word. They would have displayed varying levels of unbelief. Some would mock. Some would consider Noah’s words to be figurative. Some would want to believe but be unable to overcome the skepticism of the respectable intellectuals among them, and would compromise with them.
Believing that the flood was real, they would only consider it ‘local’. Appreciating Noah’s call to repentance they would fear the disapproval of the great men of the world even more than they feared God. It is still the same in that regard. After all, a global flood was not a ‘salvation’ issue.
Such an interpretation did not work out well for them. They drowned in their own unfaithfulness and took their followers with them.