Z is for Zadok

Zadok the Priest is an anthem, composed by George Frideric Handel for the coronation of King George II in 1727. The work has been sung prior to the anointing of the sovereign at the coronation of every British monarch since its composition and has become recognised as a British patriotic anthem.

It is based on 1 Kings 1:38–40. Lyrics from the anthem are:

Zadok the Priest, and Nathan the Prophet anointed Solomon King.
And all the people rejoiced, and said:
God save the King! Long live the King!
May the King live for ever,
Amen, Alleluia.

(okay, I know that one's not particularly modern. You try and pick one for Z, then...)