According to Hebrews, the fact that Jesus was appointed priest according to the order of Melchizedek implied that a new covenant had been inaugurated. The old covenant had been given on the basis of the Levitical priesthood (Heb. 7:11, NASB). The Levitical priests acted as mediators between God and Israel, and the law excluded anyone else from the priesthood. The author concludes, then, that a change of priesthood implies a change of the law of the priesthood, as well as a change of the covenant (Heb. 7:12, 18, 19).
The issue with the old covenant was that it could not provide perfection (Heb. 7:11). Paul is talking about the Levitical priesthood and its ministry (sacrifices, feasts, and so on). The animal sacrifices offered through them could not provide true, total cleansing from sin, nor direct access to God (Heb. 10:1–4; 9:13, 14; 10:19–23).
The fact that a new covenant was necessary does not mean that God was unfair with Israel when He gave them the old covenant. The Levitical ministry and the services of the tabernacle were designed to protect them from idolatry and also to point them to Jesus’ future ministry. Hebrews stresses that the sacrifices were “a shadow of the good things to come” (Heb. 10:1, NKJV).
By pointing them to Jesus, the sacrifices should have helped the people put their hope and faith in “the Lamb of God who takes away the sin of the world” (John 1:29, NKJV; compare with Isaiah 53). This is the same point that Paul makes when he says that the law was “our tutor to lead us to Christ, so that we may be justified by faith” (Gal. 3:24, 1995NASB) or that “Christ is the culmination of the law so that there may be righteousness for everyone who believes” (Rom. 10:4, NIV).
In other words, even the Ten Commandments, as good and perfect as they are, cannot provide salvation (Rom. 3:20–28; 7:12–14). They provide a perfect standard of righteousness, but they do not provide righteousness, any more than looking in a mirror can erase the wrinkles of age. For perfect righteousness, we need Jesus as our Substitute.
The promise of a new covenant in Hebrews refers back to Jeremiah. According to Jeremiah, God’s promise of a new covenant was, in fact, a renewal of the covenant that He had first made with Israel through Moses (Jer. 31:31–34). It could be argued, then, that Jeremiah 31 was not speaking strictly of a “new” covenant but of a “renewal” of the original covenant with Israel.
The issue with the old covenant was that the people broke it (Heb. 8:8, 9). The covenant was not faulty; the people were. If Israel had seen through the symbols to the coming Messiah and put their faith in Him, the covenant would not have been broken. Yet, to be fair, there were many believers throughout Israelite history in whom the purposes of the covenant were fulfilled and who had the law in their hearts (Pss. 37:31; 40:8; 119:11; Isa. 51:7).
Jeremiah’s promise of a “new covenant” did not simply envision a renewal of the conditions that existed before the exile, which had been broken and renewed several times because the nation had lapsed several times into apostasy. And that’s because the people were simply unwilling to keep up their end of the covenant with God (Jer. 13:23).
Thus, God promised to do a “new thing” (Jer. 31:22). The covenant would not be like the covenant that God had made “with their fathers” (Jer. 31:32). Because of the unfaithfulness of the people, the promises that God made under the Mosaic covenant were never fulfilled. Now, in virtue of the guarantee given by the Son (Heb. 7:22), God would fulfill the purposes of His covenant. God did not change His law or lower His standards; instead, He sent His Son as a guarantee of the covenant promises (Heb. 7:22; 6:18–20).