Unison (optional 2-part, optional congregation) and organ.

Notes: Hearing the Gospel, the Word of Christ amongst us, is one of the high points of the Eucharist. to greet the Gospel, a sung Alleluia (or Praise to you, O Christ in Lent) can give the reading the importance it deserves. For some churches, a reader will read from the lectern, in others the Gospel will be preceded by a long, grand procession. Most churches will do something between these two. They could be sung in any of the following ways:
1) Alleluia/Acclamation just sung once.
2) Alleluia/Acclamation sung once by the choir then repeated by the congregation and choir
(with or without descant)
3) Alleluia/Acclamation sung once or twice followed by the verse and then the Alleluia again
with or without the descant.