The Holy Eucharist is “the source and summit of the Christian life.” (CCC 1324)

— “And he took bread, and when he had given thanks he broke it and gave it to them, saying, ‘This is my body which is given for you. Do this in remembrance of me.’ And likewise the cup after supper, saying, ‘This cup which is poured out for you is the new covenant in my blood.'” (Lk 22:19-20)
— “Do not doubt whether this is true, but rather receive the words of the Savior in faith, for since He is truth, He cannot lie.” (Saint Cyril, Commentary on the Gospel of Luke)