Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred that redeems them from the transgressions committed under the first covenant. For where a will is involved, the death of the one who made it must be established. For a will takes effect only at death, since it is not in force as long as the one who made it is alive.
The last post ended with an examination of Hebrews 9:15, in which the inspired Hebrew writer says that Christ is “the mediator of a new covenant.” This is a point the Hebrew writer had spoken of in chapter 8. There he had quoted the Old Testament prophecy that a new covenant would replace the covenant made with Israel at Mt. Sinai (Jeremiah 31:31-34; Hebrews 8:6-12), pointing out that the new covenant made the old covenant “obsolete,” “growing old,” and “ready to vanish away” (8:13).
Thus, it is made clear that Christians are required to obey the New Testament rather than the Old Testament. This is a theme brought out repeatedly throughout the New Testament. A apostolic conference was called in Jerusalem in which the Spirit of God guided the apostles to determine that Gentile Christians were not required to obey the tenets of the Law of Moses save for prohibitions against “things polluted by idols,” “sexual immorality,” “what has been strangled,” and “blood” (Acts 15:19-20). Paul wrote to his Jewish Christian brethren at Rome that they have “died to the law through the body of Christ” – referring to the law of Moses – and now belonged to Christ, making the point with the analogy of a woman who is free to remarry when her first husband has passed away (Romans 7:1-4). The reason for writing the book of Galatians was to rebuke Judaizing Christians who were trying to require obedience to the Law of Moses as a requirement for salvation.
Jesus himself, while living as a Jew under the Law of Moses, encouraged his Jewish listeners to follow it while also bringing out that he had come to “fulfill” rather than abolish it (Matthew 5:17-19). Much misunderstanding exists concerning his statement in verse 18: “For truly, I say to you, until heaven and earth pass away, not an iota, not a dot, will pass from the Law until all is accomplished.” Many understandably but mistakenly conclude that the Old Testament Law of Moses would be in effect “until heaven and earth pass away.” Yet that’s not all Jesus said. He also said that “not an iota, not a dot, will pass from the Law UNTILL ALL IS ACCOMPLISHED.”
When was all accomplished? When Jesus died on the cross. Right before he died, John wrote that Jesus knew “that all was now finished” and purposefully said, “I thirst” in order to fulfill an Old Testament Messianic prophecy about receiving vinegar to drink (John 19:28-29; cf. Psalm 69:21). Upon receiving that sour wine, he said, “It is finished” before giving up his spirit in death (John 19:30). The apostle Paul under inspiration recognized this as when the Old Testament was replaced with the New. He wrote to the Ephesian Gentile Christians who lacked unity with Jewish Christians that Christ “has broken down in his flesh the dividing wall of hostility by abolishing the law of commandments expressed in ordinances” (Ephesians 2:14-15), thus bringing reconciliation both Jew and Gentile to God in one body “through the cross” (v. 16). In other words, it was at the cross when “the law of commandments” (the law of Moses) was abolished. He made the same point to the Colossian Christians by writing that Christ “canceled the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross” (Colossians 2:14). For this reason he told them that no one could pass judgment on them regarding the dietary and holy day restrictions found in the Law of Moses (vs. 16-17).
The Hebrew writer makes the same point in Hebrews 9:15-17, quoted above. Christ’s new covenant is basically his will or testament (i.e., “New Testament.”) As with any will, it would not go into effect until after the death of the one who made it. While the one who made it was still alive, it would not be in force. Therefore, the Old Testament was replaced with the New Testament when Jesus died.