Thus Heb. 7:22 calls Jesus the "surety" or "guarantee" of the new covenant, which is better than that which came through Moses. Within the context of this last passage repeated mention is made of God's promise to Christ and his people. He will be their God and they will be his people. He will bestow on them the grace they need to confess his name and live with him forever; in humble dependence on him for their every need, they will live in trustful obedience from day to day. This latter, called faith in Scripture, is the sole condition of the covenant, and even it is a gift of God (Eph. 2:8 - 9).
Although the covenant of grace includes various dispensations of history, it is essentially one. From the promise in the garden (Gen. 3:15), through the covenant made with Noah (Gen. 6 - 9), to the day that the covenant was established with Abraham, there is abundant evidence of God's grace. With Abraham a new beginning is made which the later, Sinaitic covenant implements and strengthens. At Sinai the covenant assumes a national form and stress is laid on the law of God. This is not intended to alter the gracious character of the covenant, however (Gal. 3:17 - 18), but it is to serve to train Israel until the time would come when God himself would appear in its midst. In Jesus the new form of the covenant that had been promised by the prophets is manifest, and that which was of a temporary nature in the old form of the covenant disappears (Jer. 31:31 - 34; Heb. 8). While there is unity and continuity in the covenant of grace throughout history, the coming of Christ and the subsequent gift of the Holy Spirit have brought rich gifts unknown in an earlier age.
These are a foretaste of future blessedness when this present world passes away and the Holy City, the New Jerusalem, comes down out of heaven from God (Rev. 21:2).