Under the old covenant, the people of God were commanded to offer several different sacrifices to the Lord. We are all probably quite familiar with the burnt offering, which was given to turn away God’s wrath, and the sin offering, which was sacrificed in order to cleanse the worshipper from sin’s defilement (Lev. 1; 4). But there were also sacrifices of thanksgiving, given as an expression of the worshipper’s thanks for the Lord’s many blessings (7:11–18; 22:29–30).
The sacrifice of thanksgiving is one that would have been part of our worship even if Adam never fell. Sin’s entrance into the world made the burnt offering, the sin offering, and, ultimately, the offering of Christ necessary for fellowship with God. Yet even in a sinless world, we would have been required to show the Lord thanks for all He has given to us. Thanksgiving is an essential part of true worship, and the failure to give thanks to the Lord is one of humanity’s gravest sins (Rom. 1:18–21). We would have offered sacrifices of thanksgiving even in an unfallen world.
How much more, then, should we who have been redeemed from sin offer sacrifices of thanksgiving to our Creator today? God has not dealt with His people as they deserve but has atoned for their sin and restored fellowship with them through His Son (3:21–26). A life of thanksgiving is the only proper response to His grace.
This is the point that the Apostle Paul makes in today’s passage. In Romans 1–11, Paul outlines the grace of God in the salvation of His people from sin and their rescue from His just wrath. Since we have been saved through Christ, how should we respond? Paul answers this question in Romans 12–16, and the first thing he tells us is that we should “present [our] bodies as a living sacrifice, holy and acceptable to God” (12:1). The kind of sacrifice the Apostle is talking about must be the sacrifice of thanksgiving, because Jesus offered Himself up as the burnt offering, sin offering, and peace offering for our sake (Rom. 3:21–26; Eph. 2:14).
The sacrifice of thanksgiving that God desires is a “living sacrifice” (Rom. 12:1), which is a striking metaphor. Sacrifices are dead but we are alive — as living people, we are to consider ourselves dead men, “dead to sin and alive to God in Christ Jesus” (6:11). We thank God by living as He does in holiness and righteousness.
Without an understanding of the grace of God and submission to Christ’s lordship, we cannot dedicate ourselves to the Lord in thanksgiving. Sanctification follows justification; the ability to walk in holiness is a benefit that results from our having been crucified with Christ, as question and answer 43 of the Heidelberg Catechism tell us. But if we are truly in Christ, we want to thank Him by loving His law and practicing it for the sake of holiness.