Churches of a liturgical bent usually include the “memorial acclamation” as part of their communion liturgy. The leader says “Let us proclaim the mystery of faith” and the people respond with “Christ has died. Christ is risen. Christ will come again.” This not only makes for good liturgy, but is a profound miniature creed.
Here, both parts are sung. The introduction is given to the leader–probably a cantor/soloist, but it’s wonderful when a pastor/priest is able to sing the liturgy. The acclamation is sung first by the choir (in this case a choir of Gregs) and then repeated by the congregation (of Gregs).