Easter has much to do with Baptism or vice versa. Baptized into the death of Christ we believe that we also are baptized into His resurrection and will be raised at the last day. The water images are all over the place and there is the image of Jesus death being verified but the issue of blood and water from His pierced side.
There is an interesting connection to a prophecy that probably doesn’t get much contemplation today. In Ezekiel 47 he saw a stream coming out from the right side of the future Temple, seen in a series of visions, and it kept growing until it became a river, which it was impossible to cross, teeming with fish, making every kind of fruit tree grow on its banks, bearing fruit in all seasons and flowing into the dead sea and making its water viable and sweet (Ez.47). Then we have the water bursting forth from the side of Jesus when the soldiers punch a lance into His side. The “natural” suggestion is that these two things are related in prophecy. Jesus is the one who calls His body the temple – “Destroy this temple and in three days I will raise it up again” (John .2,19). This water from the side of Jesus was for many of the early church Fathers a symbol of baptism, figured also by the all-curing and life-giving water described by Ezekiel, since it purifies from sin and bestows grace, that we may bear abundant fruit spiritually (John.15,8).
This concept was brought into the liturgy of Easter which had an antiphon called Vidi aquam: “I saw water coming out from the right side of the temple, alleluia! And all those, whom this water reached, were saved and will say: Alleluia, alleluia!” Then followed a verse from Ps. 117: “Praise the Lord for he is good, for eternal is he mercy.” It contained these references from Ezekiel and to Saint John and applied their texts to baptism.
Back in the day baptisms were held on the Easter vigil. The strength of our baptism comes from the Passion and death of Jesus. The blood of Jesus Christ cleanses us from all sin, the water of baptism purifies us and the Holy Spirit in baptism makes us spiritually fruitful, in that just as Christ was raised from the dead by the glory of the Father we who are baptized are free to lead a new life.