Noah continued to call his people to believe in Allah for nine hundred fifty years. Allah the Almighty said: And indeed We sent Noah to his people, and he stayed among them a thousand years less fifty years (inviting them to believe in the Oneness of Allah (Monotheism), and discard the false gods and other deities). Surah 29: 14
It happened that every passing generation admonished the succeeding one not to believe Noah and to wage war against him. The father used to teach his child about the matter that was between himself and Noah and counsel him to reject his call when he reached adulthood. Their natural disposition rejected believing and following the truth.
Noah saw that the number of believers was not increasing, while that of the disbelievers was. He was sad for his people, but he never reached the point of despair.