Passover is always on the 14th day of the month of Nisan. For Gentiles, the date when Passover occurs can sometimes seem a bit confusing. But, the Bible is clear:
The LORD’s Passover begins at twilight on the fourteenth day of the first month
Unlike the Gregorian calendar that we use, the Jewish people (to this day) keep basically the same Lunar calendar as they did during the time of Christ. Passover always falls on the 14th day of the Jewish month of Nisan. Also worth nothing is that a Biblical day runs from sunset to sunset:
And God said, “Let there be light,” and there was light. God saw that the light was good, and he separated the light from the darkness. God called the light “day,” and the darkness he called “night.” And there was evening, and there was morning - the first day. Genesis 1:3-5
We also know from Scripture that Jesus was crucified on Passover:
“You know that after two days is the Passover, and the Son of Man will be delivered up to be crucified.” Matthew 26:2
Now on the first day of Unleavened Bread, when they killed the Passover lamb, His disciples said to Him, “Where do You want us to go and prepare, that You may eat the Passover?” Mark 14:12
Wherever he goes in, say to the master of the house, ‘The Teacher says, “Where is the guest room in which I may eat the Passover with My disciples?” Mark 14:14
On nightfall of the 14th day, Jesus celebrates the Passover with his disciples. During this Feast, Jesus reveals the true meaning of their rehearsals: Jesus shows how his body literally is the Passover.
We have added our own comments (in parenthesis below) to illustrate that the context of what Jesus was saying, at the time, was understood by everyone in the room with Him... sadly, this seems to get missed 2,000 years later:
While they were eating (the Passover), Jesus took bread, and when he had given thanks, he broke it and gave it to his disciples, saying, “Take and eat; this is my body.”(this unleavened bread, which represents sinless-ness in my body. This bread that you have been breaking for 2,000 years - this is the body of the Messiah, which will be broken for you).
Then he took a cup, and when he had given thanks, he gave it to them, saying, “Drink from it, all of you. This is my blood of the covenant, which is poured out for many for the forgiveness of sins (this cup that you have been drinking from on Passover for 2,000 years is My blood)
There has been much division over 'Communion' throughout the history of the Church, but in the context of the Truth of Passover, there is no confusion.
Jesus is the bread & the cup of Passover!
Jesus literally is our Passover, as Paul states in 1 Corinthians 5:7:
Get rid of the old yeast, so that you may be a new unleavened batch - as you really are. For Christ, our Passover lamb, has been sacrificed.
Interesting side note about Jesus as the bread: He was born in Bethlehem, which in Hebrew means “house of bread”.