How do we know that the Torah is Divine?

Examine the evidence.

“For ask now regarding the early days that were before you, since the day that God created man upon the earth, and from one end of the heavens to the other end of the heavens, whether there was anything like this great thing, or was the likes of it heard? Did ever a people hear God’s voice speaking out of the midst of the fire as you have heard, and live?” Deuteronomy 4:32-35, Torah