Normally Jerusalem had a population between 25000 and 30000. But during the Feast season it had expanded to about 250000 or even 300000. Groups of people, Jews and proselytes, descended upon the city from various places throughout the land and from further afield. They found lodgings within the city walls or places to stay in the immediate vicinity. They came to celebrate the Passover and the Feast of Unleavened Bread.
For each households a lamb was sacrificed at the Temple, where its blood would be spilled. In each home, where people would gather together, its fresh was roasted and after sundown it would be eaten as a memorial.
This was done in memory of the first Passover when the people of Israel were delivered from slavery by the mighty hand of God. When the blood of a lamb was placed on the doorposts and lintel of the entrance of their homes. Death was stalking the land of their captivity. But God had said to them: "When I see the blood, I will pass over you."
Jesus was also in Jerusalem. And he and his disciples were celebrating the Passover together. The time of fulfilment had arrived.
. . . the Lord Jesus on the night when he was betrayed took bread, and when he had given thanks, he broke it, and said, "This is my body, which is for you. Do this in remembrance of me." In the same way also he took the cup, after supper, saying, "This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me."
- 1 Corinthians 11:23-26 ESV
The amazing historical events experienced by the people of Israel provided the prophetical backdrop for a far greater eternal deliverance that Jesus has provided for all people groups.