3 And he shall sit as a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness.
The Book of Mormon, 3 Nephi 24:1-4
1 …Thus said the Father unto Malachi–Behold, I will send my messenger, and he shall prepare the way before me, and the Lord whom ye seek shall suddenly come to his temple, even the messenger of the covenant, whom ye delight in; behold, he shall come, saith the Lord of Hosts.
2 But who may abide the day of his coming, and who shall stand when he appeareth? For he is like a refiner’s fire, and like fuller’s soap.
3 And he shall sit as a refiner and purifier of silver; and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness.
4 Then shall the offering of Judah and Jerusalem be pleasant unto the Lord, as in the days of old, and as in former years.
The Doctrine and Covenants, Section 13:1
1 Upon you my fellow servants, in the name of Messiah I confer the Priesthood of Aaron, which holds the keys of the ministering of angels, and of the gospel of repentance, and of baptism by immersion for the remission of sins; and this shall never be taken again from the earth, until the sons of Levi do offer again an offering unto the Lord in righteousness.
Scriptural Teachings of the Prophet Joseph Smith :171
Thus we behold the keys of this Priesthood consisted in obtaining the voice of Jehovah that He talked with him [Noah] in a familiar and friendly manner, that He continued to him the keys, the covenants, the power and the glory, with which He blessed Adam at the beginning; and the offering of sacrifice, which also shall be continued at the last time; for all the ordinances and duties that ever have been required by the Priesthood, under the directions and commandments of the Almighty in any of the dispensations, shall all be had in the last dispensation, therefore all things had under the authority of the Priesthood at any former period, shall be had again, bringing to pass the restoration spoken of by the mouth of all the Holy Prophets; then shall the sons of Levi offer an acceptable offering to the Lord.
Scriptural Teachings of the Prophet Joseph Smith :173
These sacrifices, as well as every ordinance belonging to the Priesthood, will, when the Temple of the Lord shall be built, and the sons of Levi be purified, be fully restored and attended to in all their powers, ramifications, and blessings. This ever did and ever will exist when the powers of the Melchizedek Priesthood are sufficiently manifest; else how can the restitution of all things spoken of by the Holy Prophets be brought to pass. It is not to be understood that the law of Moses will be established again with all its rites and variety of ceremonies; this has never been spoken of by the prophets; but those things which existed prior to Moses’ day, namely, sacrifice, will be continued. It may be asked by some, what necessity for sacrifice, since the Great Sacrifice was offered? In answer to which, if repentance, baptism, and faith existed prior to the days of Christ, what necessity for them since that time? The Priesthood has descended in a regular line from father to son, through their succeeding generations.