Other than the third Sunday of Advent (Gaudete Sunday), priests also don rose-colored vestments on the fourth Sunday of Lent which the church calls Laetare Sunday.
Similar to the meaning of Gaudete, the Latin word Laetare as well means “rejoice”. On Laetare Sunday, the Catholic Church which observes fasting and penance during Lent manifests joy and hope for the glorious resurrection of the Lord on Easter. Like the solemnities and feasts celebrated within the season of Lent, the Church also puts on halt penitential observations during Laetare Sunday.
As the rest of the Lenten season is symbolized with the penitential color purple, the rose color’s bright hue symbolizes joy and hope in the midst of the season of penance.
In Holy Masses on this day, the celebration starts with the entrance antiphon, “Rejoice, Jerusalem, and all who love her. Be joyful, all who were in mourning; exult and be satisfied at her consoling breast.” (Isaiah 66:10–11) As we hear these words of Prophet Isaiah, let us be assured of the joyful exultation and consolation that Christ would bring to us in his glorious resurrection.
Laetare Sunday: https://www.simplycatholic.com/laetare-sunday/