"Behold, the days are coming, declares the LORD, when I will make a new covenant with the house of Israel and the house of Judah, not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the LORD. For this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people." — Jeremiah 31:31-33 ESV
Among the six covenants of the Bible, the Mosaic and the new covenants are the most similar to each other. They are the only covenants God established with the nation of Israel rather than with individuals, albeit through mediators: Moses and Jesus Christ respectively. As revealed through the book of Jeremiah 31:31-33, the old and new covenants share two elements in common, namely the act of redemption and the law. A third shared element that plays an important role in the two covenants is the sign of the covenant.
The act of Redemption
God’s act of redemption (Exodus 12-14) in delivering the Israelites from slavery in the land of Egypt echoes with God’s act of redemption by delivering God’s people from the slavery to sin. The first act of redemption was essential to the Mosaic covenant while the second, core to the new covenant. God’s direct involvement and initiation in the plans of redemption is a striking similarity between the two covenants. In Exodus 3:8 God speaks to Moses from the burning bush, declaring: “I have come down to deliver them out of the hand of the Egyptians”. In the same way, Jesus, the one “mediator between God and men” (1 Timothy 2:5) came down in the flesh calling people to “repent, for the kingdom of heaven is at hand” (Matthew 4:17). The physical exodus of the Israelites from the land of Egypt paints a picture of the future redemption through the sacrificial offering of Jesus Christ.
The law plays a crucial role not only in the sphere of the two covenants but also in God’s entire plan of salvation. A considerable portion of Scripture is dedicated to establishing three categories of laws for the nation of Israel, namely the civil, the ceremonial, and the moral laws. These laws were given to the Israelites to observe and obey their God who brought them “out of the land of Egypt, out of the house of slavery” (Exodus 20:2). This act of redemption was at the very beginning of the giving of the law which was also set as a reminder for their obedience. However, obedience to the law could not give life (Galatians 3:21). Apostle Paul writes to the Galatians that the law was but a mere guardian until Christ came to bring justification by faith (Galatians 3:24). That is why God announced through the prophet Jeremiah: “I will put my law within them, and I will write it on their hearts” (Jeremiah 31:33). It is not by accident that the central focus of the Pentateuch is Leviticus 16 – The Day of Atonement. The most important event in the observing of the law reminds the Israelites of the first Passover and their exodus out of Egypt on the one hand, and even more significant it foreshadows Jesus’ atonement once and for all on the other hand. At the end of the “Sermon on the Mount”, Jesus confirms His purpose as “not to abolish”, “but to fulfil” the law (Matthew 5:17). Through His perfect obedience to the law and His sacrifice on the cross Jesus not only offered Himself as the ultimate and only sufficient sacrifice but also fulfilled the role of the perfect high priest who is without sin (Hebrews 4:15). Finally, when sending His disciples to fulfil the Great Commission, Jesus commanded that the new disciples be taught “to observe all that I commanded you” (Matthew 28:20). The obedience from now on can only come from a changed heart as announced through Jeremiah, a heart that has God’s moral law (the only law renewed in the new covenant) written on it.
The Sign of the Covenant
The signs of the Mosaic covenant and of the new covenant are the Passover and the Lord’s Supper. Both are ordinances with continuity in their observance. Before bringing out the Israelites out of the land of Egypt, God gave precise instructions for the ordinance of the Passover which He emphasised again in the context of the giving of the law (Leviticus 23; Numbers 28; Deuteronomy 16). The Passover lamb, being slaughtered and its blood shed, points to the symbolic meaning of God’s redemptive Lamb and His precious blood shed for sinners. The bread and wine at the Lord’s Supper are also symbols of the same Lamb and His blood. Another similarity concerning the two ordinances can be found in the instructions for their administration. Firstly, God instructs Moses and Aaron to tell the Israelites to “remove leaven out” of their houses (Exodus 12:15). Later in Scripture apostle Paul allegories leaven with “malice and evil” (1 Corinthians 5:8). Both texts call for consecration and separation from evil. In the context of the Lord’s Supper this is reinforced by apostle Paul calling participants to examine themselves before partaking in this ordinance (1 Corinthians 11:28). Subsequently, God commands that “no foreigner shall eat” of the Passover meal (Exodus 12:43), unless circumcised (Exodus 12:44, 48), as circumcision symbolises the adoption into the native land (Exodus 12:48). A similar requirement is made by the apostle Paul to the church in Corinth by calling them to “discern the body” before eating and drinking of the Lord’s Supper (1 Corinthians 11:29), lest they “be guilty concerning the body and blood of the Lord” (1 Corinthians 11:27).
The Mosaic covenant is related organically and progressively to the totality of God's redemptive purposes. It ultimately finds its consummation in Jesus Christ, the author of a better covenant (Hebrews 8:10-12), the better mediator (Hebrews 3:3), and the “founder and perfecter of our faith” (Hebrews 12:2).