Matthew 26:19

‘And the disciples did as Jesus appointed them, and they made ready the Passover.'

Note the emphasis on the obedience of the disciples. The Lord was always to be obeyed. Their obedience was to be an example to all. Matthew never put in redundant words. And the result was that they made all the necessary preparations for the Passover, including the sacrificing of the lamb in the Temple and then the bringing of it to the appointed house ready for the meal. The houseowner may well himself have provided the unleavened bread, the vegetables, the bitter herbs, the sauces and the wine. All was now ready for the final Passover. Once this was over God's final deliverance would have been accomplished, and Passover would no longer have any significance (even though it would continue to be observed by Christian Jews. They would, however, give it a new meaning).