Judaism is a national religion. It provenance rests upon a claim of national revelation. It is recorded in the Torah the entire people accepted the "yoke of Heaven." The author's point being it is easier for an individual to lie than for an entire nation to adopt a fabricated account of its own history. Indeed Maimonides writes the Torah the Jewish people received at Sinai is the one and only revelation and nothing will ever supersede the Torah. Thousands of years have passed and nothing has yet superseded the words God spoke to an entire nation at the mountain in Sinai.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus