Therefore he assured him by an oath, that he would bless the nations in his seed, and that he would multiply him as the dust of the earth, and exalt his seed as the stars, and cause them to inherit from sea to sea, and from the river to the utmost part of the land.
Read Chapter 44
The inheritance that he was promised symbolizes two things. The comparison with the sand of the sea indicates the Jews, who are sterile. And the comparison with the stars of heaven designates all the people who believe in Christ, who by the light of the resurrection will shine like the stars of heaven. "Every star in fact differs from another in splendor. So also in the resurrection." His descendents will inherit "from one sea to the other, from the river to the ends of the earth," since Christ, born of the descendents of Abraham, rules from one sea to the other and from the river to the ends of the earth, and his church, his very body, fills all the limits of the world. One also notes that Abraham represents in himself three things. In the first place, the Savior, who, leaving his family, came into this world. Second, the Father, when he sacrificed his only Son. Third, by the fact that he had welcomed three men and adored one of them, he symbolized the saints, who joyfully received the coming of Christ in the flesh. This mystery of the incarnation is the work of the entire holy Trinity but was realized only in the Son. "And the Word was made flesh and came to dwell among us." - "On Ecclesiasticus 10.5"