O Clavis David

 20 December is the fourth day of the Great  #OAntiphons:

O Clavis David (chant with neumes)

O Clavis David, et sceptrum domus Israel;

qui aperis, et nemo claudit;

claudis, et nemo aperit:

veni, et educ vinctum de domo carceris,

sedentem in tenebris, et umbra mortis. 

Literally:

   O Key of David and scepter of the house of Israel,

   you who open and no one closes

   who close and no one opens,

   come, and lead the bound one from the prison house,

   the one sitting in gloom and the shadow of death.

in the Household Book of Blessings and Prayers:

   O Key of David,

   opening the gates of God’s eternal Kingdom:

   come and free the prisoners of darkness!

in “Veni Emmanuel”:

   Veni clavis Davidica!

   Regna reclude coelica,

   Fac iter Tutum superum,

   Et claude vias Inferum.

   Gaude, gaude, Emmanuel

   nascetur pro te, Israel.

in “O Come, O Come Emmanuel”:

   O come, Thou Key of David, come

   And open wide our heav’nly home;

   Make safe the way that leads on high,

   And close the path to misery.

   Rejoice! Rejoice! Emmanuel

   Shall come to thee, O Israel.