The alleluia response is notated in ¢3, which has semibreve equivalency with ¢ – the meter for the verse. The dotted half note of the alleluia should be the same as the half note of the verse. As often occurs in ¢3 meter, a hemiola is imbedded in the tenor and bass voices in the first and second measures and again as the tenor approaches the cadence at the end of the alleluia. Metrical emphasis should be placed accordingly. Isaac’s textual use is on display in the verse as imitative polyphonic duets predominate until the words “adorare Domini”.
Alleluia. Vidimus stellam ejus in Oriente, et venimus cum muneribus adorare Dominum. Alleluia.
Alleluia. We have seen his star in the East and come with gifts to adore the Lord. Alleluia.