The Feast of Corpus Christi, also known as the Solemnity of the Most Holy Body and Blood of Christ, is a Catholic celebration of the real presence of Jesus Christ in the Eucharist—and thus a sacred reminder that, in every Mass, Jesus’ one sacrifice of Calvary is sacramentally made present and  offered anew for “the forgiveness of the sins we daily commit” (CCC 1366).

The Church celebrates Corpus Christi to profess and adore our Eucharistic Lord. Jesus is truly present body, blood, soul, and divinity in the Eucharist. Further emphasizing that at every Mass we partake of the Lamb of God, the New Covenant Passover sacrifice. Not only that, this feast highlights the sacramental and sacrificial reality of Christ’s presence. Additionally, it affirms the Church’s teaching on transubstantiation, and invites the faithful into deeper Eucharistic devotion.

(See Catholic Answers https://www.catholic.com/tract/feast-of-corpus-christi-what-it-is-when-its-celebrated-and-why-it-matters)