The Book of Mormon retains an opening phrase (bolded v. 31) that attributes to the Lord the action referred to in these verses, and also retains a more definite identification (bolded v. 32). The King James text is the same as that not bolded.
Joseph Smith, in writing of the persecution he and other Saints had suffered in Missouri, said: “We refer you to Isaiah, who considers those who make a man an offender for a word, and lay a snare for him that reproveth in the gate (v. 32, or 21). We believe that the old Prophet verily told the truth, and we have no retraction to make” (TPJS, 124).