Let All Mortal Flesh...

One of my favorite hymns is "Let All Mortal Flesh Keep Silence," taken from the 5th century Liturgy of St. James. I like it both for its text and for the French carol it's set to, PICARDY. The current, common harmony is taken from The English Hymnal, 1906 (see my post, below). Here is the text, as presented in a few hymnals, translated by Gerard Moultrie (1829-1885) (some have some verses, others have others):

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 nature,
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 pow'rs 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.

These verses are taken from the Anaphora of the liturgy. Notable is the second verse, Christ giving himself for heavenly food. It is absent from some hymnals, among them the Baptist, while included in others (even those of the Protestant type). However, in Protestant hymnals (Episcopalians, Lutherans and the new Methodist hymnal excluded), this hymn is usually placed in the Advent section, or Christmas if there is no Advent section.

I've had churches sing this during Advent, and they generally react positively to it. The last couple of years, I've had our church sing it on our communion Sunday in Advent, which is more fitting given its history. But, should Protestants be singing it at all? Christ giving his own self for heavenly food doesn't bother me, because that can be interpreted many ways; but, does it confuse? Noone has ever asked me about it. I would prefer it to go away from the Advent section, personally, especially in those hymnals that leave out the second verse—the only one which specifically mentions the first advent.

But, would singing it at communion be appropriate at a Baptist church? I often feel like people have no idea what they're singing, anyway, so would it wake them up? And, I wonder how Orthodox Christians would feel about Baptists singing part of the Divine Liturgy?