The prophet Isaiah admonished those in his day to fast with unselfish purposes. He declared, “Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke?” (Isaiah 58:6).
What is teaching with the “spirit of prophecy”? (6:8) Declaring the word of God “according to the spirit of prophecy” is to teach the gospel by the power of the Holy Ghost by witnessing one’s knowledge of Jesus Christ. John declared that the “testimony of Jesus is the spirit of prophecy” (Revelation 19:10). Joseph Smith explained, “God in his superior wisdom has always given his Saints, wherever he had any on the earth, the same spirit, and that spirit, as John says, is the true spirit of prophecy, which is the testimony of Jesus’” (History of the Church, 5:400).
The superscription to Alma 7 was part of the ancient record translated by the Prophet Joseph Smith and dictated by him to his scribe (see also, for example, 2 Nephi, Mosiah 9, and Alma 21).
The italicized words “Comprising chapter 7” were not part of the ancient record but were added later to printed editions of the Book of Mormon.