What are the differences between the Old Covenant and the New Covenant?

from the old testament

• The "Old Covenant" is a term used to refer to God's covenant with Israel, given through Moses at Mount Sinai (Exodus 19:5–6; Exodus 24:7–8). In a broader sense, it correlates with the books of the Old Testament.
• Starting in Genesis 12, God called Abraham to form a nation, set apart to reveal His holiness, and through whom the Messiah, Jesus, would come (see Galatians 3:16). God promised to bless Abraham and make him a great nation (Genesis 12:1–2). The covenant was formalized in Genesis 15 through a sacrifice and vision (Genesis 15:1–20), and in Genesis 17, circumcision was established as the covenant sign for all male descendants and those joining Israel.
• The Old Covenant, often connected with the Mosaic Law, was made with the Israelites—Abraham’s descendants—after their deliverance from Egypt. The Ten Commandments, including the Sabbath as a sign, form its foundation, with God declaring, "I am the LORD your God, who brought you out of the land of Egypt" (Exodus 20:2). God promised to bring them into the land He had sworn to Abraham (Exodus 6:2–8) and gave laws covering justice, hygiene, food, festivals (Leviticus 23), and worship. The tabernacle, with its Holy of Holies housing the ark of the covenant and mercy seat, was central to worship, with Aaron’s priesthood mediating between God and the people; only the high priest could enter the Holy of Holies once a year on the Day of Atonement (Leviticus 16). Obedience brought blessings, like fertility and prosperity, while disobedience brought curses, such as disease and defeat (Deuteronomy 27–28).
• The Old Covenant was not intended to be permanent (Jeremiah 31:31–34; cf. Hebrews 8:6–13).

from the new testament

• The "New Covenant" refers to the covenant mediated by Jesus through His death and resurrection (1 Timothy 2:5–6; Luke 22:20; Hebrews 8:6–13).
• Jesus perfectly fulfilled the Old Covenant and ushered in the promised New Covenant (Matthew 5:17–18; 27:26–29; Hebrews 8:6). In a broader sense, the New Covenant correlates with the books of the New Testament.
• The New Testament book of Hebrews gives a detailed explanation of the differences between the Old Covenant and the New Covenant, explaining how Jesus fulfilled the Old Covenant and ushered in the New. Hebrews 10:1 says, "the law has but a shadow of the good things to come instead of the true form of these realities."
• The elements of the Old Covenant pointed toward their ultimate fulfillment in Jesus. Rather than continual animal sacrifices to make payment for sin, Jesus "offered for all time a single sacrifice for sins… For by a single offering he has perfected for all time those who are being sanctified" (Hebrews 10:12, 14).
• Unlike a priest who needed to sacrifice for his own sins first, Jesus "has no need, like those high priests, to offer sacrifices daily, first for his own sins and then for those of the people, since he did this once for all when he offered up himself" (Hebrews 7:27).
• Rather than restrictions around the ark of the covenant and God's presence, "we have confidence to enter the holy places by the blood of Jesus, by the new and living way that he opened for us through the curtain, that is, through his flesh, and since we have a great priest over the house of God, let us draw near with a true heart in full assurance of faith, with our hearts sprinkled clean from an evil conscience and our bodies washed with pure water" (Hebrews 10:19–22).
• Gentiles—non-Jewish people from all nations—are welcomed into the New Covenant without needing to follow Jewish laws like circumcision (Galatians 5:2–6; 6:15). Paul explains that no one can be made right with God by obeying the Law alone because the Law’s purpose is to reveal sin (Romans 3:20). Instead, God’s righteousness is now available through faith in Jesus Christ to everyone who believes, regardless of their background (Romans 3:21–22).
• This faith in Jesus makes believers heirs to the promises God made to Abraham, showing that salvation is by grace through faith, not by works (Galatians 3:7–9). Thus, all who trust in Jesus are included in God's blessing and counted as Abraham’s spiritual descendants.
• While under the Old Covenant, relationship with God was mediated through a sacrificial system; now, all who put their faith in Jesus receive the indwelling Holy Spirit. Rather than a physical temple where God's presence dwells, His Spirit dwells in us (Galatians 3:14; 4:4–7; Ephesians 1:3–14; 1 Corinthians 6:19–20).

implications for today

It is important to recognize that the Old Covenant itself was never a means of salvation. It pointed to God's holiness, revealed humanity's sinfulness, preserved a family line through whom the Messiah would come, and gave civil regulations for a nation. Salvation has always been by God's grace through faith. Atonement for sin has always depended on Jesus's work on the cross. Under the Old Covenant, faith was demonstrated by obedience to God's laws. Under the New Covenant, our faith is in Jesus Christ. The Old Covenant pointed forward to Jesus's work. The New Covenant looks back to His work and allows us to enter into the godly life made possible because of it.

Jesus beautifully demonstrated the relationship between the Old Covenant and the New Covenant the night before His crucifixion. The Passover meal was the annual remembrance of God's rescue of Israel from slavery in Egypt, particularly the final plague in which God killed the firstborn of the Egyptians. With the blood of a sacrificial lamb on their doorposts, the Israelites were spared. That lamb ultimately represented Jesus—"the Lamb of God, who takes away the sin of the world" (John 1:29; cf. 1 Peter 1:18–21). When Jesus took the bread that night, He said, "'Take, eat; this is my body.' And he took a cup, and when he had given thanks he gave it to them, saying, 'Drink of it, all of you, for this is my blood of the covenant, which is poured out for many for the forgiveness of sins'" (Matthew 26:26–28). Jesus fulfills the Old and has ushered in the New Covenant. May His name be praised!