Think about it and read John's account...
You should know the lamb is part of the meal.
Numbers 9:11-12 They must celebrate Passover just before dark on the 14th day of the second month. At that time they must eat the lamb, the bread made without yeast, and the bitter herbs. They must not leave any of that food until the next morning. And they must not break any of the bones of the lamb. They must follow all the rules about Passover.
Luke 22:7-9 Easy-to-Read Version (ERV)
The Passover Meal
7 The Day of Unleavened Bread[a] came. This was the day when the Jews always killed the lambs for the Passover. 8 Jesus said to Peter and John, “Go and prepare the Passover meal for us to eat.”
9 They said to him, “Where do you want us to prepare the meal?”
He said to them,
Mark 14:12-15 Easy-to-Read Version (ERV)
The Passover Meal
12 It was now the first day of the Festival of Unleavened Bread—the day the lambs were killed for the Passover. Jesus’ followers came to him and said, “We will go and prepare everything for you to eat the Passover meal. Where do you want us to have the meal?”
13 Jesus sent two of his followers into the city. He said to them, “Go into the city. You will see a man carrying a jar of water. He will come to you. Follow him. 14 He will go into a house. Tell the owner of the house, ‘The Teacher asks that you show us the room where he and his followers can eat the Passover meal.’ 15 The owner will show you a large room upstairs that is ready for us. Prepare the meal for us there.”
Now the first day of the feast of unleavened bread the disciples came to Jesus, saying, Where will You that we prepare for You to eat the Passover? And He said, Go into the city to such a man, and say unto him, The Master says, My time is at hand; I will keep the Passover at your house with My disciples.
By the first day of the feast of unleavened bread, he means the day before that feast; for they are accustomed always to reckon the day from the evening, and he makes mention of this in which in the evening the passover must be killed; John 13:1 for on the fifth day of the week they came unto Him. And this one calls the day before the feast of unleavened bread, Luke 22:7 speaking of the time when they came to Him, and another says on this wise, Then came the day of unleavened bread, when the passover must be killed; by the word came, meaning this, it was near, it was at the doors, making mention plainly of that evening. For they began with the evening, wherefore also each adds, when the passover was killed.
And they say, Where will You that we prepare for You to eat the passover? So even from this it is manifest, that He had no house, no place of sojourning; and I suppose neither had they. For surely they would have entreated him to come there. But neither had they any, having now parted with all things.
But wherefore did He keep the passover? To indicate by all things unto the last day, that He is not opposed to the law.
And for what possible reason does He send them to an unknown person? To show by this also that He might have avoided suffering. For He who prevailed over this man's mind, so that he received them, and that by words; what would He not have done with them that crucified Him, if it had been His will not to suffer? And what He did about the ass, this He did here also. For there too He says, If any man say anything unto you, you shall say, that the Lord has need of them; Matthew 21:3 and so likewise here, The Master says, I will keep the passover at your house. But I marvel not at this only, that he received Him, being unknown, but that expecting to bring upon himself such enmity and implacable hostility, he despised the enmity of the multitude.
After this, because they knew him not, He gave them a sign, like as the prophet touching Saul, saying, You shall find one going up and carrying a bottle; 1 Samuel 10:3 and here, carrying a pitcher. And see again the display of his power. For He did not only say, I will keep the passover, but He adds another thing also, My time is at hand. And this He did, at once continually reminding His disciples of the passion, so that exercised by the frequency of the prediction, they should be prepared for what was to take place; and at the same time to show to themselves, and to him that was receiving Him, and to all the Jews, which I have often mentioned, that not involuntarily does He come to His passion. And He adds, with my disciples, in order that both the preparation should be sufficient, and that the man should not suppose that He was concealing Himself.
Now when the evening had come, He sat down with the twelve disciples. Oh the shamelessness of Judas! For he too was present there, and came to partake both of the mysteries, and of the meal, and is convicted at the very table, when although he had been a wild beast, he would have become tame.
For this cause the evangelist also signifies, that while they are eating, Christ speaks of His betrayal, that both by the time and by the table he might show the wickedness of the traitor.
For when the disciples had done, as Jesus had appointed them, when the evening had come, He sat down with the twelve. And as they did eat, He said, we are told, Verily, I say unto you, that one of you shall betray me. And before the supper, He had even washed his feet. And see how He spares the traitor. For He said not, such a one shall betray me; but, one of you, so as again to give him power of repentance by concealment. And He chooses to alarm all, for the sake of saving this man. Of you, the twelve, says He, that are everywhere present with me, whose feet I washed, to whom I promised so many things.
CHURCH FATHERS: Homily 81 on Matthew (Chrysostom)
Acts 15
From the apostles and elders, your brothers,
To all the non-Jewish brothers in the city of Antioch and in the countries of Syria and Cilicia.
Dear Brothers:
24 We have heard that some men have come to you from our group. What they said troubled and upset you. But we did not tell them to do this. 25 We have all agreed to choose some men and send them to you. They will be with our dear friends, Barnabas and Paul. 26 Barnabas and Paul have given their lives to serve our Lord Jesus Christ. 27 So we have sent Judas and Silas with them. They will tell you the same things. 28 We agree with the Holy Spirit that you should have no more burdens, except for these necessary things:
29 Don’t eat food that has been given to idols.
Don’t eat meat from animals that have been strangled or any meat that still has the blood in it.
Don’t be involved in sexual sin.
If you stay away from these, you will do well.
We say goodbye now.