O Come Thou Branch of Jesse's Tree

 "Who was Jesse?" you may ask.  He was a member of the house of Judah in the nation of Israel.  He had several sons, and the youngest--David--was chosen by God to be King of all Israel.  Some thousand years later, Jesus was born of Mary, one of David descendants.  Joseph, Jesus's earthly father, was also a descendant of David. 

Here is the Medieval antiphon written about him and used for December 19:

O Root of Jesse, standing as an ensign before the peoples,

Before whom all kings are mute, to whom the nations will do homage:

 Come quickly to deliver us.

And the verse by John Mason Neale:

O come, thou Branch of Jesse's tree,

Free them from Satan's tyranny

That trust thy mighty power to save,

And give them victory o'er the grave:

 Rejoice, rejoice, Emmanuel shall come to thee, O Israel.