From the beginning of the book of Sh'mot all the way through the rest of the Torah, just about everything that happened was witnessed by millions of people - men, women, and children.
All those people can verify the stories of the Torah. They can tell them to their children, and their children will tell them to their children ... and on and on until we hear them from our parents and teachers, and we tell our children and grandchildren those same stories.
Except for what happened in the first 95 p'sukim of Parshat Balak. Sadly, the last 9 p'sukim of shame to the people of Israel, are part of the collective knowledge of the Jewish People. Recorded in the Torah and passed on through the generations.
But the 95 p'sukim story of Balak and Bil'am were witnessed by Balak and Bil'am and their attendants.
We the people of Israel were TOTALLY unaware of what was taking place on a hilltop or two or three. We were oblivious to it all. We did not realize the serious danger we were in.
And we would still not know anything about it - surely Bil'am and Balak would not have told the story of their failure to their own people, let alone to the rest of the world.
We know the story because G-d dictated it to Moshe who wrote it down in the Torah that G-d was giving to the People of Israel.
We need to be especially appreciative to G-d for fighting for us. Usually, He fights side-by-side with us. The battle against Amalek was cooked by the army that Joshua drafted, and G-d pledged to fight with us.
The only time He volunteered for us without our participation was when we first came out of Egypt and an elite army pursued us towards the Sea. We did not fight, but we observed. And appreciated. And sang our thanks.
But with Bil'am and Balak, it was G-d all the way. (Until we messed up.)
G-d handled the Balak / Bil'am threat for us. It was a special gift and we must thank G-d extra for it.