Verse five is given in language that Mormon intentionally parallels to a prophecy of the coming of the Messiah:
Mosiah 3:5
5 For behold, the time cometh, and is not far distant, that with power, the Lord Omnipotent who reigneth, who was, and is from all eternity to all eternity, shall come down from heaven among the children of men, and shall dwell in a tabernacle of clay, and shall go forth amongst men, working mighty miracles, such as healing the sick, raising the dead, causing the lame to walk, the blind to receive their sight, and the deaf to hear, and curing all manner of diseases. (italics added).
The Savior was to come and miracles of healing were to be done. Mormon shows that the twelve continue this healing mission of the Messiah. While the Book of Mormon phrase set is longer, it is similar to one in the New Testament:
Matthew 11:5
5 The blind receive their sight, and the lame walk, the lepers are cleansed, and the deaf hear, the dead are raised up, and the poor have the gospel preached to them.
The similarity suggests that Joseph’s vocabulary was influenced by the New Testament, just as we have seen multiple times. However, the extended version, and more complete citation, that we see between Helaman and 4 Nephi, suggests that the core phrase is indeed Mormon’s and that there is an intentional repetition given here to highlight the fulfilled prophecy.