Both Isaiah and Jacob knew the future. Earth will return to paradisiacal glory, as stated in Articles of Faith 1:10. The Book of Mormon is certainly part of the law that will proceed from the Lord in the last days, a portion of the restoration of all things that will enlighten all who look for light.
Law, light, righteousness, salvation, and judge are all name-titles for the Savior of the world, the one Person in whom we can implicitly trust.