The Easter antiphon, and the Easter replacement for the Angelus.
The Marian antiphon of Eastertide, and the prayer that replaces the Angelus for those fifty days.
When: From the Easter Vigil through Pentecost. Prayed at morning, noon, and evening in place of the Angelus, and after Night Prayer as the seasonal antiphon.
Why: Every line ends in alleluia. It is the Church telling the Mother who stood at the Cross that the sorrow is over, and then asking her to continue praying for us.