To Thy Seed, Which Is Christ: The Covenants Made with the Seed and the One Seed They Were Made For
Old Testament: Genesis 17:7; Genesis 22:18
And I will establish my covenant between me and thee, and between thy seed after thee in their generations, by a perpetual covenant: to be a God to thee, and to thy seed after thee. ... And in thy seed shall all the nations of the earth be blessed, because thou hast obeyed my voice.
Old Testament, also: Isaias 59:21
This is my covenant with them, saith the Lord: My spirit that is in thee, and my words that I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed's seed, saith the Lord, from henceforth and for ever.
New Testament: Galatians 3:16, 29; Romans 11:27; Luke 1:55
To Abraham were the promises made and to his seed. He saith not, And to his seeds, as of many: but as of one, And to thy seed, which is Christ. ... And if you be Christ's, then are you the seed of Abraham, heirs according to the promise. ... And this is to them my covenant: when I shall take away their sins. ... As he spoke to our fathers, to Abraham and to his seed for ever.
The connection
God never makes a covenant with one man alone. To Noe: "Behold I will establish my covenant with you, and with your seed after you" (Genesis 9:9). To Abraham: "I will establish my covenant between me and thee, and between thy seed after thee ... by a perpetual covenant" (17:7), and, after Isaac was given back on the mountain, "in thy seed shall all the nations of the earth be blessed" (22:18). Phinees receives "the covenant of the priesthood for ever ... to him and his seed" (Numbers 25:13), and Esdras, praying after the exile, remembers the covenant made with Abraham "to give it to his seed: and thou hast fulfilled thy words, because thou art just" (2 Esdras 9:8). Isaias hears the fullest form of it: "My spirit that is in thee, and my words that I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed's seed" (Isaias 59:21). St Paul reads the word closely: "He saith not, And to his seeds, as of many: but as of one, And to thy seed, which is Christ" (Galatians 3:16). Every covenant made with the seed was waiting for one Seed. Paul brings us into it: "if you be Christ's, then are you the seed of Abraham, heirs according to the promise" (3:29). He quotes Isaias too, "And this is to them my covenant", and names what it does: "when I shall take away their sins" (Romans 11:27). Mary sings that the promise has been kept, "As he spoke to our fathers, to Abraham and to his seed for ever" (Luke 1:55). St Irenaeus says that "they who have believed in Christ do receive Christ, the promise to Abraham". St Augustine tells the doubters of his day to look around them: "see how in the whole world all nations are blessed in Abraham's seed. Abraham, in his day, believed what was not yet seen". The Catechism teaches that the progeny promised to Abraham is Christ Himself, in whom the Holy Ghost gathers into one the scattered children of God (CCC 706).
Moral sense
The promise is received by belonging to Christ: "if you be Christ's, then are you the seed of Abraham". Isaias's covenant keeps the Spirit and the word in the mouth of "thy seed's seed", generation after generation, and every Christian is somebody's seed's seed. The word reached us because it did not depart from someone else's mouth. St Augustine sees why the promised son came to Abraham in his old age: "He came when all things were growing old, and made them new."
Anagogical sense
The covenant's first words, "to be a God to thee, and to thy seed after thee" (Genesis 17:7), are spoken for the last time at the end: "they shall be his people; and God himself with them shall be their God" (Apocalypse 21:3). "He that shall overcome shall possess these things, and I will be his God; and he shall be my son" (21:7). The children of Abraham, gathered into the one Seed, inherit the promise that was made to them before they were born.
The Fathers
St Irenaeus, Against Heresies V.32: "he plainly declares that they who have believed in Christ do receive Christ, the promise to Abraham". St Augustine, Letter LXXVI: "see how in the whole world all nations are blessed in Abraham's seed. Abraham, in his day, believed what was not yet seen; but you who see it refuse to believe what has been fulfilled." St Augustine, Sermons on the New Testament, on Matthew 18:7: "Therefore was there a son born to Abraham in his old age, because in the old age of this world was Christ to come. He came when all things were growing old, and made them new."
Warrant
Scriptural because St Paul names the seed of the promise as Christ (Galatians 3:16), reading Genesis 22:18, and quotes Isaias 59:21 at Romans 11:27. Checked in the Hebrew and the Greek: the promise uses zera, seed, a collective singular, and the Septuagint keeps the singular, en to spermati sou at Genesis 22:18; Galatians 3:16 has kai to spermati sou, hos estin Christos. Romans 11:27 has kai haute autois he par' emou diatheke, word for word the Septuagint of Isaias 59:21, and takes its last clause from Isaias 27:9. St Irenaeus (Against Heresies V.32) and St Augustine (Letter LXXVI, and often) read the promise of the seed as Paul does. Phinees's covenant of an everlasting priesthood (Numbers 25:13; Ecclesiasticus 45:30) is kept in the One who "hath an everlasting priesthood" (Hebrews 7:24). Dunk found the entry by noticing that God's covenants are made with the seed from Noe to Isaias.
Catechism of the Catholic Church, paragraph 706.
The verses
Genesis 17:7 · Genesis 22:18 · Isaias 59:21 · Galatians 3:16 · Galatians 3:29 · Romans 11:27 · Luke 1:55
