"In your descendants all the nations of the earth shall find blessing" (Gn 28,14)
The genealogy of Jesus Christ from St. Matthew's Gospel is read to us. It is a custom handed down by holy Church with a beauty and mystery of its own. For behold how in truth this reading puts before us at dead of night that ladder which Jacob saw at night in his sleep (Gn 28,12). Supported on the topmost rung of the ladder where it reached heaven the Lord appeared to Jacob and promised him that his posterity would inherit the earth... Now, as we know, "all these things happened to them in figure" (1Cor 10,11). The ladder by which the Lord appeared to be supported prefigured the family-tree of Jesus Christ which the holy Gospel-writer so drew up as to come through Joseph. It is by Joseph that our Lord as a small child is supported. Through the gate of heaven (Gn 28,17)..., that is, through the Blessed Virgin, our Lord, a tiny child for our sake, comes crying... The words that Jacob in his sleep heard the Lord say, "And in thy posterity shall all the nations of the earth be blessed", are fulfilled by the birth of Christ.
The divine writer, bearing in mind this very point, put the names of Rahab the prostitute and Ruth the Moabite into his genealogy. For he saw that Christ was made flesh not for the Jews alone, but also for the Gentiles, inasmuch as he deigned to accept ancestors from among the Gentiles... Sprung therefore from two races, Jew and Gentile, as from two sides of the ladder, the ancestors from their different rungs support Christ our Lord emerging from heaven. The holy angels come up and go down and all the elect are first humbled to receive faith in his Incarnation that they may be afterward lifted up to see the glory of his divinity.