What the seraphim do in line 396a of the Old English Advent: a scribal cover uncovered

A word in the Old English 'Advent' or 'Christ I' was amended to fit the rhyme and meter of the poem. The word, meaning 'to guard', is more suitable since the poem has allusions to Isiah 6:2. The word was probably mispelled and emended by the scribe who copied the poem. The word is located in Line XI which glorifies the Advent and introduces the Seraphim, a class of angels which sing praises to the Lord.