1 Peter 2:5, ESV
Because in these last days, God chose you, in Jesus Christ, to exemplify how man ought to worship God. About 350 years after the priesthood was instituted, the priests despised God's rules, fattening themselves off the sacrifices and committing adultery with the female servants of the tabernacle (1 Samuel 2:12-17, 22). nearly 1000 years after the institution of the priesthood, God rebuked them for their contempt in Malachi 1:6-14. "Better to make no sacrifices at all than to keep up the charade!" God laments in Mal 1:10.
But God wasn't satisfied with dissolving the priesthood. Malachi 3:1-3 describes His plan. The Lord would come to the temple and refine—purify the Levites to offer to the Lord an offering in righteousness, no longer in show! This is a picture of us. The Lord Jesus sacrificed Himself, entered the Holiest of Holies by His blood, and there made atonement for our sins before the Father (Heb 9:11-12, 14). Now we are purified from our former sins (2 Peter 1:9) and are fit to offer to God sacrifices in righteousness, acceptable to Him: "the fruit of lips giving thanks to His name" (Hebrews 13:15, KJV).