Gaude et laetare

A traditional Latin introit hymn sung on the Fourth Sunday of Lent, known as Laetare Sunday. The hymn’s title, meaning “Rejoice, O Jerusalem,” is taken from the opening words of Isaiah 66:10–11. The use of "Laetare Jerusalem" dates back to at least the early Middle Ages and forms part of the Roman Gradual, the official liturgical book for chants.