What I did communicate is that the Last supper was not a seder meal. The Last supper was not the Passover meal in which the Passover lamb was consumed. The Gospel according to saint John has Jesus arrested
before the Passover lamb is sacrificed and the Last supper was eaten
before Jesus was arrested therefore the Last supper cannot have been the meal in which Israel's people were to eat the lamb sacrificed for Passover because the lamb was sacrificed
before the seder meal was eaten. The Gospel according to saint Matthew presents Jesus as dying at the time that the Passover lamb was sacrificed in the temple (at the ninth hour). -
Matthew 27:45-50 45 Now from the sixth hour there was darkness over all the land until the ninth hour. 46 And about the ninth hour Jesus cried out with a loud voice, saying, Eli, Eli, lema sabachthani? that is, My God, my God, why have you forsaken me? 47 And some of the bystanders, hearing it, said, This man is calling Elijah. 48 And one of them at once ran and took a sponge, filled it with sour wine, and put it on a reed and gave it to him to drink. 49 But the others said, Wait, let us see whether Elijah will come to save him. 50 And Jesus cried out again with a loud voice and yielded up his spirit.
So the Gospels present Jesus as God's Passover lamb sacrificed (crucified and dead) at the time that the Passover lamb was killed in accord with the Law of Moses.