Natasha levchenko,
There are many different days that people celebrate, but most do not celebrate the ONE that Jesus said to celebrate as a Memorial to him until he comes back to earth, Luke 22:14-20, 1Corinthians 11:23-26.
This date is Nisan 14, of the Old Jewish calendar. This date, like most Memorial dates come on different days of the week, each year. This year athe Memorial is on Saturday, March 31, and it must be after sunset, because the Jews celebrated the old calendar, in which the days of the week started in the evening, and ended the next evening. When Jesus was killed he had to be taken down from the cross, or stake, before evening, because the next Day was a Sabbath, a Great Sabbath, because it was a Saturday, and the Saturday happened to fall on the Passover date.
The reason that we celebrate the Memorial of Jesus’ death, is because he purposely came to earth to give his life for us, so we could gain back what Adam and Eve lost for us, when they rebelled against God, Genesis 2:17, 3:6. When they disobeyed Their Creator, and sinned, they became imperfect, and began to die. God never meant for them to die, they were supposed to multiply and fill the earth and subdue all have in subjection all the animals, Genesis 1:26-28.
Out of great love for God, who sent His son ti give his life for us as a Corresponding Ransom Sacrifice for us, so that when and if we died we could be resurrected from death, back to life in a Paradise earth. Jesus actually died for all mankind, but only the ones who believe in him and follow his teaching, and Footsteps, will be saved, 1Peter 2:21.
You can imagine how much love that God had for His son, and the love that Jesus had for us and his Father. God loved the world so much that He allowed His son to give his life for all mankind, who love him and His Father.
That is the reason we celebrate the Memorial, because of the great love they both showed for us, John 3:16. On the night before his death, Jesus told his dis piles to remember that one night, and continue to celebrate that date, until he returns to earth.