The Kuzari and its author, Rav Yehuda Halevi do some comparative religion. He brings a Pasuk from last week's Parsha to prove his point.
Moshe Rabbeinu actually tells the people the following: "Has G-d ever attempted to take one nation from the midst of another nation with signs and wonders, as He did in Egypt?"
The Kuzari is saying to look at the origin of each religion and how it began. Judaism began with the witnessing of supernatural miracles as well as the revelation from Hashem Himself. Every Jew of all ages heard G-d speak!
Can any other religion make such a claim of the masses witnessing beyond any doubt, the existence of G-d and His connection to His people. And even more impressive is that the other major religions acknowledge that these events actually occurred.
Moshe is strengthening the people before his death so that they pass this along to every generation. There must be no doubt to the truth and authenticity of the Jewish religion.