Laus tibi, Domine, Rex æterne gloriæ.
Praise to Thee, Lord, King of eternal glory!
This is the cry of the penitent Church in her Office from Compline after first Vespers of Septuagesima till Compline of Wednesday in Holy Week inclusive, having laid aside the glad Alleluia that is not resumed until either the joyful Mass of Easter in completion of the solemn Paschal Vigil, or, for those not present thereat, at the start of Easter Matins.
Now, I resolved that a good way to remember this, and not just mechanically say the A-word by mistake at the start of each Hour, was to blog about it, and so fix it the more in my mind.
(Note that the Anglicans since 1662 long said at Matins and Evensong, after the opening Glory be, the versicle and response "Praise ye the Lord; The Lord's Name be praised" - which arose from Cranmer's rendering of the Alleluia and Laus tibi together as "Praise ye the Lord", and the turning of this, first in the Scottish Prayer Book of 1637, into a versicle for the minister not the people, who were assigned a new counterpart phrase, based on Sit nomen Domini benedictum and laudabile nomen Domini in Ps 112:2 and 3.)
But why this phrase? Well, Hallelujah means "praise the Lord", and this, put into the vocative gives Laus tibi, Domine - "Praise (be) unto Thee, (O) Lord". The second half of the full phrase, Rex æterne gloriæ - "(O) King of eternal glory" - forms together with the first half a rough rhyming couplet, and this is a common form in the Breviary apparently stemming from mediæval days, being used for blessings at Matins. Of course, God is named the King of glory four times in Psalm 23:7-10; and the Te Deum sings Tu Rex gloriæ, Christe - "Thou art the King of glory, O Christ": in both cases, Their Kingship and glory is eternal; God shall live and reign in perfect Trinity "as it was in the beginning, is now, and ever shall be, world without end. Amen."