Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened. For indeed Christ, our Passover [πάσχα], was sacrificed for us.

The real meaning of Easter - which is really Passover; Jesus Christ the Son of God, born of a virgin, crucified on a cross, buried but rose again three days later, having defeated Satan and therefore death. The shedding of his blood will save from judgement and therefore hell all who believe.  A believer needs to purge out sin, represented here by leaven, because such a person has new life - has been born again.