As they..were eating,

Palm_sunday Jesus said, "Amen I say to you, one of you will betray me, one who is eating with me."  They began to be distressed and to say to HIm, one by one, "Surely it is not I?" He said to them, "One of the Twelve, the one who dips with Me into the dish...It would be better for that man if he had never been born."

While they were eating, He took the bread, said the blessing, broke it, and gave it to them and said, "Take it:  This is my body." (Mark 14:18-26)

And likewise the cup, saying, "This is My blood, the new covenant, which will be shed for many for the forgiveness of sins." (Matthew 26:28)