Malachi employed powerful symbolism by describing the Messiah’s coming “like a refiner’s fire, and like fuller’s soap” (3 Nephi 24:2). A refiner is “a man who separates the precious metals from the dross with which in nature they are usually found mixed. Part of the process consists in the application of great heat, in order to bring the mass into a fluid state, hence the term ‘refiner’s fire’” (Bible Dictionary, “Refiner,” 760).
The Savior is like a refiner. Elder Bruce R. McConkie (1915–85) of the Quorum of the Twelve Apostles explained: “His mission is to cleanse, purify, and refine the human soul so that it can return to his Father’s kingdom in purity, free from dross. (3 Ne. 27:19–21.) His cleansing power ‘is like a refiner’s fire, … And he shall sit as a refiner and purifier of silver’ in that great day when he comes to judge the world. (Mal. 3:2–3; 3 Ne. 24:2–3; D.&C. 128:24)” (Mormon Doctrine, 2nd ed. [1966], 624).
A fuller’s “work was to cleanse garments and whiten them” through the use of soap (Bible Dictionary, “Fullers,” 676). The Atonement of Jesus Christ acts like “fuller’s soap” to cleanse us from our sins and prepare us to stand pure and spotless before the judgment seat.