The first part of the sermon deals with the Gospel for the day (the parable of the workers in the vineyard - you can read the whole thing here) but he concludes by saying:
We willað eow secgan be ðyssere andweardan tide, hwi seo halige gelaðung forlæt on Godes cyrcan ‘Alleluian’ and ‘Gloria in excelsis Deo’, fram ðisum andwerdum dæge oð þa halgan Eastertide. Sum wis lareow hatte Amalarius, se awrat ane boc be cyrclicum ðeawum, hwæt ða gesetnyssa Godes þenunga of gearlicum ymbryne getacniað, and cwæð be ðyssere andwerdan tide, þe is gecweden Septuagesima, þæt heo gefylð ða getacnunge þæra hundseofontig geara þe Israhela folc on hæftnede Babiloniscum cyninge þeowde. Septuagesima is hundseofontigfeald getel. Seo tid onginð on ðisum Sunnandæge, nigon wucon ær Eastron, and geendað on ðam Saternesdæge þære Easterlican wucan: to ðam daæge sind heonon getealde hundseofontig daga; and þæt Israhela folc, for heora mandædum and forgægednyssum, wurdon gehergode, and hundseofontig geara on Babiloniscum þeowdome, buton blisse and myrhðe, wunodon. Nu hylt Godes gelaðung þis hundseofontigfealde getel sylfwilles for hire gyltum, swa swa se ealda Israhel neadunge heold on hæftnunge, oðþæt se mildheorta God eft, æfter heora gedrefednyssum, hi ahredde, and to heora earde gelædde.
Se witega Hieremias witegode be ðære Israhela ðeode, þæt hi sceoldon, on ðam hund-seofontig geara fæce, geswican blisse stemne and fægnunge, brydguman stemne and bryde. Nu on ðære gelicnysse forlætað Godes ðeowas ða heofonlican lofsangas, ‘Alleluian’ and ‘Gloria in excelsis Deo,’ on ðissere Septuagesima, forðan þe us gedafenað þæt we sylfwilles fram ðisum andwerdan dæge mid sumere stiðnysse to ðam gastlicum gefeohte us sylfe gegearcian, swa swa seo cyrclice þenung us manað to heofunge and to ure synna bereowsunge. Ærest on ðære mæssan officio we singað ‘Circumdederunt me gemitus mortis’: ‘Deaþes geomerunga me beeodon, and helle sarnyssa me beeodon, and ic on minre gedrefednysse Drihten clypode, and he of his halgan temple mine stemne gehyrde.’ Eft, on ðære mæssan collectan we cweðað, ‘Qui juste pro peccatis nostris affligimur,’ þæt is, ‘We ðe rihtlice for urum synnum sind geswencte.’ Eac se apostol on ðam pistole cwæð, ‘Ælc ðæra þe on gecampe winð, forhæfð hine sylfne fram eallum ðingum.’
Witodlice ðas dægðerlican ðenunga cyðað þæt fram ðisum dæge oð Eastron is ure heofungtid and bereowsungtid ure synna mid sumere stiðnysse. ‘Alleluia’ is Ebreisc word, þæt is on Leden ‘Laudate Dominum,’ and nan gereord nis swa healic swa Ebreisc. Nu forlæte we þæt healice gereord on ure Septuagesima, and cweðað on Leden, ‘Laus tibi, Domine, Rex aeterne gloriae’; þæt is, ‘Sy ðe, Drihten, lof, eces wuldres Cyning.’ We geswuteliað mid þære eadmodan Leden spræce, þæt we sceolon us sylfe to eadmodran drohtnunge on ðyssere tide gebigan. ‘Alleluia’ is, swa we cwædon, heofonlic sang, swa swa Iohannes se apostol cwæð, þæt he gehyrde micele stemne on heofonum, swylce bymena dream, and hi sungon ‘Alleluian.’ ‘Gloria in excelsis Deo’ sungon englas, þaþa Crist on middanearde lichamlice acenned wæs. Nu forlæte we ðas heofonlican lofsangas on ure bereowsung-tide, and we biddað mid soðre eadmodnysse ðone Ælmihtigan, þæt we moton geseon his heofenlican Easter-tide, æfter þam gemænelicum æriste, on ðam we him singað ecelice Alleluian butan geswince. Amen.
'We wish to speak to you about this present season, why the holy congregation in God’s church omits ‘Alleluia’ and ‘Gloria in excelsis Deo’, from this present day until the holy season of Easter. There was a wise teacher named Amalarius, who wrote a book about the church’s customs and what the ceremonies of God’s servants symbolise through the course of the year; and he said about this present season, which is called Septuagesima, that it acts as a token of the seventy years for which the people of Israel served the king of Babylon in captivity. Septuagesima is the number 'seventy'. The season begins on this Sunday, nine weeks before Easter, and ends on the Saturday in Easter week; from now until that day are counted seventy days, and the people of Israel, for their sins and transgressions, were taken into captivity and lived for seventy years in slavery to Babylon, without joy and bliss. Now God’s church keeps this period of seventy, by choice, for their sins, just as Israel of old was forced to keep it in captivity, until merciful God rescued them after their tribulations and led them to their homeland.
The prophet Jeremiah prophesied about the people of Israel that during that period of seventy years they should cease from the voice of joy and gladness, the voice of the bridegroom and the bride. Now in emulation of that, God’s servants leave the heavenly songs of praise, ‘Alleluia’ and ‘Gloria in excelsis Deo’, in this period of Septuagesima, because it is fitting for us that from this present day we prepare ourselves voluntarily with a degree of austerity for the spiritual battle, as the liturgy of the church exhorts us to sorrow and repent of our sins. First in the Office of the Mass we sing ‘Circumdederunt me gemitus mortis’, ‘The mournings of death surrounded me, and the pains of hell surrounded me, and I cried to the Lord in my trouble and he heard my voice from his holy temple.’ Then in the Collect of the Mass we say, ‘Qui juste pro peccatis nostris affligimur’, that is, ‘We who are justly afflicted for our sins.’ Again, the apostle in the Epistle says, ‘Every one of those who strives in battle withholds himself from all things.’
Truly the liturgy of the day shows that from this day until Easter is our season of mourning and season of repenting for our sins with a degree of austerity. ‘Alleluia’ is a Hebrew word – that is in Latin, ‘Laudate Dominum’ – and no language is as holy as Hebrew. Now we leave that holy language in our Septuagesima, and say in Latin, ‘Laus tibi, Domine, Rex aeterne gloriae’, that is, ‘Praise be to thee, Lord, King of eternal glory.’ We show by our humble Latin speech that we should incline to a humbler way of living in this season. ‘Alleluia’ is, as we said, a heavenly song; as the Apostle John said that he heard great voices in heaven, like the music of trumpets, and they sang ‘Alleluia’. ‘Gloria in excelsis Deo’ sang the angels, when Christ became incarnate in flesh in this world. Now we leave the heavenly songs of praise in our season of repentance, and we pray with true humility to the Almighty, that we may see his heavenly Eastertide, after the general resurrection, in which we will sing ‘Alleluia’ to him eternally without ceasing. Amen.'
Hanging up harps by the waters of Babylon (BL Harley 603, f. 70, 11th century)
It's interesting to see Ælfric's opinion on the relative holiness and humbleness of Hebrew and Latin! This is Ælfric at his best as a teacher, clearly and concisely explaining to his congregation both the liturgical practices associated with Septuagesima and the reasons for them. There's a good deal of learning here, lightly worn, as Ælfric moves confidently between Latin, Ebreisc and English, between the texts of the liturgy, the Old Testament, and the New. His last paragraph touches on a similar idea to the Septuagesima hymn 'Alleluia dulce carmen' (glossed as 'Alleluia, myrige leoþ' in one Anglo-Saxon manuscript of hymns), which J. M. Neale translated as 'Alleluia, song of sweetness':
'Alleluia', song of sweetness,
voice of joy that cannot die;
'alleluia' is the anthem
ever raised by choirs on high;
in the house of God abiding
thus they sing eternally.
'Alleluia' thou resoundest,
true Jerusalem and free;
'alleluia', joyful mother,
all thy children sing with thee;
but by Babylon's sad waters
mourning exiles now are we.
'Alleluia' cannot always
be our song while here below;
'alleluia' our transgressions
make us for awhile forgo;
for the solemn time is coming
when our tears for sin must flow.
Therefore in our hymns we pray thee,
grant us, blessed Trinity,
at the last to keep thine Easter,
in our home beyond the sky,
there to thee for ever singing
You can find the tune to 'Alleluia dulce carmen' here.
'Alleluia dulce carmen' in an Anglo-Saxon hymnal (BL Cotton MS Vespasian D XII, f.48v)