By building the ark Noah was not only obedient to God, he was also seeking salvation. Obeying God was the only way to be saved. And he also preached that people should repent to be saved. In 2 Peter 2:5 Noah is called the “herald of righteousness.” In word and deed, he showed people the only way to salvation. In this way he condemned those who did not want to listen. Jesus said that those who believe will be saved and whoever does not believe will be condemned (Mark 16:16).
7 By faith Noah, being warned by God concerning events as yet unseen, in reverent fear constructed an ark for the saving of his household. By this he condemned the world and became an heir of the righteousness that comes by faith.