Icons made by Eastern Christians are very complex, and there are meanings behind each elements. Even colours hold various meanings; for example; red represents divinity, while blue stands for humanity. Jesus usually has a red tunic, symbol of His divinity, and a blue cloak for He took on our humanity. Mary on the other hand is dressed in blue, representing her humanity, while her veil or mantle is red, symbol that she was clothed in divinity.
A while ago, as I was looking at a crucifix, I wondered what was the signification of the blood and the water which came out of Our Saviour’s pierced side. I had previously read this moment was when the Church was born, and although this can be debated (some claim Pentecost, others the birth of Christ or even Mary), I believe this is what makes the most sense. The blood coming out of hole from the lance represents Jesus himself, it is the blood which saved and redeemed us, the blood of the Lamb of the New Passover who was slain. Yet what does the water stand for? Water is usually a strong symbol of grace pouring down on us. Who really reflects and personifies grace? It is as the Holy Spirit said through His messenger the Archangel Gabriel “Hail, full of grace“! I suddenly remembered the prophecy of Simeon “a sword shall pierce thy heart“. If Mary is Coredemptrix and Mediatrix of all Graces, then she has an extremely important part in the birth of the Church.
In a certain way, we can say that the Church is born out of the Sacred Heart of Jesus and the Immaculate Heart of Mary. Saint Alphonse of Liguori, Doctor of the Church, actually supports this and goes in-depth with a beautiful explanation :
The second instance in which Mary gave us birth to grace, it was on Calvary. She offered to the Eternal Father, and with so much sorrow of heart, the life of her beloved Son for our salvation. Wherefore, St. Augustine asserts, that, “having then cooperated by her love to give us birth to grace, she became our mother to all, we who are the body of Jesus-Christ, who is our head.” This is also the meaning of the words of the sacred Canticles 7,3 when applied to the Blessed Virgin Mary : “They have made me the keeper in the vineyards; my vineyard I have not kept.” William the Abbot remarks that “Mary, to save our souls, was willing to sacrifice the life of her Son.” And who was the soul of Mary, but her Jesus, who was her life and all her love? Wherefore St. Simeon announced to her that her soul would one day be pierced by a sword of sorrow; which was the very spear that pierced the side of Jesus, who was the soul of Mary. And then she in her sorrow brought us forth to eternal life; so that we may all call ourselves children of the dolours of Mary. She, our most loving mother, was always and wholly united to the divine will; whence St. Bonaventure remarks, “that when she saw the love of the eternal Father for men, who would have his Son die for our salvation, and the love of the Son in wishing: to die for us, she too, with her whole will, offered her Son and consented that he should die that we might be saved, in order to conform herself to that exceeding love of the Father and Son for the human race.
The Glories of Mary; pages 42 & 43 ― adapted into English from French
To make sure that Jesus was dead one of the soldiers pierced his side with a spear. It deserves notice that he does not say “wounded” but “pierced,” that is “opened,” because in his side the door of eternal life is opened to us: “After this I looked, and lo, in heaven, an open door!” (Rev 4:1). This is the door in the side of the ark through which those animals entered who were not to perish in the flood (Gen 7).
This door is the cause of our salvation; and so, at once there came out blood and water. This is a remarkable miracle, that blood should flow from the body of a dead person where blood congeals. And if someone says that this was because the body was still warm, the flow of the water cannot be explained without a miracle, since this was pure water. This outpouring of blood and water happened so that Christ might show that he was truly human. For human beings have a twofold composition: one from the elements and the other from the humours. One of these elements is water, and blood is the main humour.
Another reason why this happened was to show that by the passion of Christ we acquire a complete cleansing from our sins and stains. We are cleansed from our sins by his blood, which is the price of our redemption: “You know that your were ransomed from the futile ways inherited from your fathers, not with perishable things, such as silver or gold, but with the precious blood of Christ, like that of a lamb without blemish or spot” (1 Pet 1:18). And we are cleansed from our stains by the water, which is the bath of our rebirth: “I will sprinkle clean water upon you, and you shall be clean from all your uncleanness” (Ez 36:25); “On that day there shall be a fountain opened for the house of David and the inhabitants of Jerusalem to cleanse them from sin and uncleanness” (Zech 13:1). And so it is these two things which are especially associated with two sacraments: water with the sacrament of baptism, and blood with the Eucharist.
Or, both blood and water are associated with the Eucharist because in this sacrament water is mixed with wine, although water is not of the substance of the sacrament.
This event was also prefigured: for just as from the side of Christ, sleeping on the cross, there flowed blood and water, which makes the Church holy, so from the side of the sleeping Adam there was formed the woman, who prefigured the Church.
Dr Brant Pitre, a modern scholar who studies how ancient Judaism is fulfilled in Catholicism says that during the Passover, the Jews would sacrifice thousands of lambs. Now all that blood had to be disposed of, and so the priests would mix it with water as it kept it from coagulating. After mixing the blood of the sacrificial lambs with water, they would drain the blood of the sacrifices from the altars into tubes who would bring it to a nearby river. So, on Passover, if you looked up at the Holy City, you would have seen this river of blood and water flowing down from the Temple’s right side! Jesus died while the Passover was going on―during the time when He as the ultimate High Priest and King was offering the perfect unblemished sacrifice for the remissions of our sins.