St Augustine of AfricaOne of the soldiers with a spear pierced His Side, and forthwith came out Blood and Water.

The Evangelist speaks carefully. He says not that he smote the Side, nor yet that he wounded It, nor yet anything else.

Rather, he pierced It, to fling wide the entrance unto life, whence flow the Sacraments of the Church, those Sacraments without which there is no entrance unto the life which is life indeed.

That Blood which was shed there was shed for the remission of sins, that Water is the water that is mingled in the cup of salvation.

Therein are we washed, and thereof do we drink.

Of this was it a type when it was said unto Noah The door of the ark shalt thou set in the side thereof, and of every living thing of all flesh shalt thou bring into the ark, to keep them alive (Gen. 6: 16, 19).

This is a figure of the Church. Thus was it that the first woman was made from the side of her husband while he slept, and she was called Eve – which is, being interpreted, Life, because she was the mother of all living.

This name set forth a great good, before it became associated with the bitter fruit of a great evil.

And here we have the Second Adam bowing His Head, and the deep sleep of death falling upon Him upon the Cross.

And He sleeps, that the Lord God may take a thing out of His side, and may make thereof a wife for Him.

O what a death was His, which quickens the dead! What is cleaner than His Blood? What more health-giving than His wounding?

Then they were held bondsmen to the devil, slaves to evil spirits. But now they have been redeemed from that bondage.

They had been able to sell themselves, but they were not able to redeem themselves.

A Redeemer came and paid the price for them. He shed His Blood, and at that cost bought the world.

Ye ask what He bought, look what He paid, and ye shall see what He bought.

Christ’s Blood was the price. What is His Blood worth? What, but the whole world! What but all men?

[…] What He paid, He paid for all.

Augustine of Hippo (354-430:  120th Tract on John, from the Feast of the Precious Blood in the Old Breviary.