This exercise asks us to listen to Handel’s Dixit Dominus and annotate the score to highlight specific ways in which the instruments are used. I listened to a performance by the Monteverdi Choir and English Baroque Soloists, conducted by John Eliot Gardiner.
I found many instances of antiphony (alternating between different voices and/or instruments), as well as imitation of rhythmic patterns. The alternation is particularly effective when it involves one part sustaining a note while the other has a melodic line, and then swapped around. Sometimes it is strict alternation, and sometimes it is overlapping, giving a sense that the new part is interrupting (e.g. in bars 69-70).
At other points in the score the instruments are supporting the voices, for example in bar 52 where the violins play in unison with the sopranos. This is an important point in the music as it is the first change in the words being sung, and the change in texture gives this a greater impact.
The basso continuo begins with a continuous quaver bass line, giving the music a feeling of momentum. At other times it repeats the rhythmic pattern that is such a feature of the piece, and towards the end of the piece plays a sustained line which builds up the tension.
I have scanned the first few pages of my annotated score here.