The text of the KJV is the same except for one phrase (v. 7). The Book of Mormon says “in whose heart I have written my law,” and the KJV says “in whose heart is my law.” In his second general epistle, the apostle Peter expressed teachings similar to the three Isaiah verses:
10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
11 Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness,
12 Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat?
13 Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness. [2 Peter 3:10–13]
The Book of Mormon retentions (see bold words in the text) calls to mind the promise given in Jeremiah that a new covenant will be established with Judah and Israel in the latter days, unlike the one when he brought them out of Egypt, but “I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people” (Jeremiah 31:31–33). This further indicates that Isaiah is referring to the latter days.