Official English text from the Liturgy of the Hours:
O King of the nations, the only joy of every human heart; O Keystone of the mighty arch of man, come and save the creature you have fashioned from dust.
Official Latin text:
O Rex gentium, et desideratus earum, lapisque angularis, qui facis utraque unum: veni, et salva hominem, quem de limo formasti.
More literal English translation:
O King of the gentiles and their desired One, the cornerstone that makes both one: come, and deliver man, whom you formed out of the dust of the earth.