Easter Sunday is the culmination of Holy Week. Easter commemorates the resurrection of Jesus Christ.
It is the most important Christian festival, and the one celebrated with the greatest joy
According to the scriptures, Jesus had his last meal with his disciples on the evening of a Thursday (commemorated as Holy Thursday), was arrested during the night, tried Friday morning (Good Friday), condemned, crucified, and died before sunset on Friday.
He was buried in a tomb and the tomb was guarded and an enormous stone put over the entrance, so that no-one could steal the body.
HE IS RISEN
On the following Sunday, Mary Magdalene, Mary the mother of James, and Salome visited the grave and found that the stone had been moved and that the tomb was empty.
The day stands for the triumph of Christ over death.
His resurrection is what ultimately makes Christians believe that he is the Son of God.
"He is risen", is the popular proclamation of this joyful day, signifying his resurrection. It also serves as a symbol of divinity.