My Favorite Hymn: Let All Mortal Flesh Keep Silence

The New Liturgical Movement features two recordings of this hymn--one in Slavonic "from the Liturgy of St James, [which] is sung at the Great Entrance in place of the Cherubic Hymn, when the Divine Liturgy of St Basil the Great is celebrated on the morning of Holy Saturday":

Let all mortal flesh keep silent, and stand with fear and trembling, and in itself consider nothing of earth; for the King of kings and Lord of lords cometh forth to be sacrificed, and given as food to the believers; and there go before Him the choirs of Angels, with every dominion and power, the many-eyed Cherubim and the six-winged Seraphim, covering their faces, and crying out the hymn: Alleluia, Alleluia, Alleluia.

And the other is the English version by Gerard Moultrie set to music by Ralph Vaughn Williams to a French carol tune called Picardy (Stephen Cleobury's arrangement):

Let all mortal flesh keep silence,
And with fear and trembling stand;
Ponder nothing earthly minded,
For with blessing in His hand,
Christ our God to earth descendeth
Our full homage to demand.

King of kings, yet born of Mary,
As of old on earth He stood,
Lord of lords, in human vesture,
In the body and the blood;
He will give to all the faithful
His own self for heavenly food.

Rank on rank the host of heaven
Spreads its vanguard on the way,
As the Light of light descendeth
From the realms of endless day,
That the powers of hell may vanish
As the darkness clears away.

At His feet the six winged seraph,
Cherubim with sleepless eye,
Veil their faces to the presence,
As with ceaseless voice they cry:
Alleluia, Alleluia
Alleluia, Lord Most High!

According to this site Gerard Moultrie was born on Sep­tem­ber 16, 1829 at Rug­by Rec­to­ry, Eng­land and died on Ap­ril 25, 1885 in South­leigh, Eng­land:

Moultrie was ed­u­cat­ed at Rug­by and Ex­e­ter Coll­ege, Ox­ford (BA 1851, MA 1856). Tak­ing Ho­ly Or­ders, he be­came Third Mas­ter and Chap­lain in Shrews­bu­ry School; Chap­lain to the Dow­ager Mar­chion­ess of Lon­don­de­rry, 1855-59; cur­ate of Bright­walt­ham, 1859; and of Brin­field, Berkshire, 1860; Chap­lain of the Don­a­tive of Bar­row Gur­ney, Bris­tol, 1864; Vi­car of South­leigh, 1869; and Warden of St. James’ Coll­ege, South­leigh, 1873. Moultrie’s works in­clude:

• The Primer Set Forth at Large for the Use of the Faith­ful, 1864
• Hymns from the Post Re­form­a­tion Edi­tions, 1864
• Hymns and Lyrics for the Sea­sons and Saints’ Days of the Church, 1867
• The Espousals of S. Dor­o­thea and Other Vers­es, 1870
• The De­vout Com­mun­i­cant, 1867
• Six Years’ Work in South­leigh, 1875
• Cantica Sanc­tor­um, or Hymns for the Black Let­ter Saints Days in the Eng­lish and Scot­tish Cal­en­dars, 1850

Looks like he was pretty High Church! 

The arrangement by Gustav Holst is very effective too.