The Eucharist is the sacrament by which Catholics receive the Body and Blood of Jesus Christ. For Catholics, this is the most treasured gift given to the Church by the Lord at the Last Supper. In receiving the Eucharist, we are nourished by the Lord. The bread and wine used in the Mass are transformed in all but appearance into the Body and Blood of Christ. The Eucharist is seen as "the source and summit" of Christian life, the participation of the faithful in God's sanctifying action through worship.