100 Seconds
Rabbi Shmuel Waldman in Beyond a Reasonable Doubt (2004) writes on pages 63-65:

In the Torah, when God wanted to reveal His will to humanity, He didn’t reveal Himself to one person in a private prophesy, He did so in front of the entire Jewish nation, as it states (Deuteronomy 4:33-36):

Has any nation ever heard God speaking out of fire, as you have, and remained alive? Has God ever done miracles bringing one nation from the midst of another nation with such tremendous trials, signs and wonders, and war, and a mighty hand and out-stretched arm, and terrifying phenomena, as God did for you in Egypt before your very eyes? You are the ones who have been shown, so that you will know that God is the Supreme Being, and there is none other besides Him. From Heaven, He let you hear His voice so as to discipline you, and on earth He showed you His great fire, and you heard His words come from within the fire.

The Torah was not given to one person who had a private vision and tried to convince others of its authenticity. It was given in broad daylight, in front of millions of people, and at that same event Moses was clearly selected as the leader and prophet of the Jewish nation. ……….. It’s almost not “belief”. The people of Moses’ time did not have to believe that he had personal revelation from God telling everyone to follow Torah. They experienced the revelation themselves. The people themselves heard as God spoke to Moses. “And God said to Moses: Behold! I [will] come to you in the thickness of the cloud, so that the people will hear as I speak to you and [thus] they also will believe in you forever” (Exodus 19:9). These words were uttered prior to God’s communicating the Ten Commandments. Subsequently, the entire people were given the privilege of prophesy by hearing the voice of God as He spoke to Moses. Thus, it was like a “conference call”- and everyone was hooked up. This was no private prophesy. All of the Jewish people clearly saw that there is prophesy – that God does speak to humans. And it also proved to the people, beyond a reasonable doubt, that God had singled out Moses to be His chosen prophet.

It had to happen this way. If God wanted to create a viable monotheistic religion, amidst a world of idol worshippers, it would only make sense for Him to reveal Himself to their leader in the presence of a large multitude, and then communicate to that leader the details of what He wanted His people to do.