The word "Torah" does not mean "law" it means "teaching" or "instruction."  Thus Christians should not talk of the "law and the prophets" but of God's "teaching and the prophets."  Torah often refers to the first five books of the Bible.  Scholars question whether Moses had any input into them.  Conservative Jews and Christians believe Moses wrote every word. The LDS position is in the middle.  The "Book of Moses" in the Pearl of Great Price indicates Moses did receive a revelation from God.  Joseph Smith described his "translation" which is more accurately described as an inspired expansion is premised on the idea the writings of Moses were inaccurately transmitted and modified over the centuries.