On the first day of Unleavened Bread, when they sacrifice the Passover lamb, His disciples asked Him, "Where do You want us to go and prepare the Passover so You may eat it?"
References for Mark 14:12
So He sent two of His disciples and told them, "Go into the city, and a man carrying a water jug will meet you. Follow him.
Wherever he enters, tell the owner of the house, 'The Teacher says, "Where is the guest room for Me to eat the Passover with My disciples?" '
He will show you a large room upstairs, furnished and ready. Make the preparations for us there."
So the disciples went out, entered the city, and found it just as He had told them, and they prepared the Passover.
When evening came, He arrived with the Twelve.
References for Mark 14:17
While they were reclining and eating, Jesus said, "I assure 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 not I?"
He said to them, "[It is] one of the Twelve-the one who is dipping [bread] with Me in the bowl.
For the Son of Man will go just as it is written about Him, but woe to that man by whom the Son of Man is betrayed! It would have been better for that man if he had not been born."
As they were eating, He took bread, blessed and broke it, gave it to them, and said, "Take [it]; this is My body."
References for Mark 14:22
Then He took a cup, and after giving thanks, He gave it to them, and so they all drank from it.
He said to them, "This is My blood [that establishes] the covenant; it is shed for many.
References for Mark 14:24
I assure you: I will no longer drink of the fruit of the vine until that day when I drink it in a new way in the kingdom of God."
References for Mark 14:25
After singing psalms, they went out to the Mount of Olives.
References for Mark 14:26