O Rex gentium

Ultimate source unknown

"O Rex gentium et desideratus earum, lapisque angularis, qui facis utraque unum:  veni et salva hominem, quem de limo formasti."

O King of the nations and their Desideratus and Cornerstone, [you] who make [us] both one:  Come and save the Man (הָֽאָדָם, ha-adam) Whom you formed of the slime [of the earth].

     O-Antiphon to the Magnificat, Vespers, 22 December, Liturgia horarum.  The ICEL version present in the Liturgy of the hours is powerful, but takes a number of liberties:

"O King of all the nations, the only joy of every human heart; O Keystone of the mighty arch of man, come and save the creature you fashioned from the dust."

Sources:

• Jer 10:7:  "quis non timebit te o rex gentium tuum est enim decus"
• Hag 2:8:  "et movebo omnes gentes et veniet desideratus cunctis gentibus"
• Isa 28:16:  "ecce ego mittam in fundamentis Sion lapidem lapidem probatum angularem pretiosum in fundamento fundatum qui crediderit non festinet" | Eph 2:20:  "superaedificati super fundamentum apostolorum et prophetarum ipso summo angulari lapide Christo Iesu" | 1 Pet 2:5:  "ecce pono in Sion lapidem summum angularem electum pretiosum et qui crediderit in eo non confundetur"
• Eph 2:14:  "ipse est enim pax nostra qui fecit utraque unum"
• Gen 2:7:  "formavit igitur Dominus Deus hominem de limo terrae"