Most of the time when I think of water turning to blood I think of the first plague God did through Moses to effect the release of the Israelites from Egypt. I usually do not remember that this was also a sign for the Israelites before the plague:
If they won’t believe even these two signs or pay attention to you, then take some water from the Nile River and pour it out on dry ground. The water that you take from the Nile will turn into blood on the dry ground.
The first two signs that were to prove that Moses was sent by God were his staff transforming into a snake and his hand becoming leprous and healing again. This was a third sign to show that God was acting through Moses and that the blessing of deliverance was about to be received by the Israelites.
When thinking of the Nile water and blood in this sign, it reminded me of Jesus’ visit to a wedding in Cana. Here water is poured out and transformed into wine, which is not exactly the same thing as blood. Yet it is the blood of a grape, in a manner of speaking. As well, Jesus would later say of wine, “This is my blood” during the Last Supper.
Keeping that in mind, what happened in Cana was very similar to what happened in Egypt around 1200-1500 years earlier. Water was transformed as a sign that God was about to act. This divine action would deliver a people who were bound in slavery, one in Egypt and one in sin and death. The transformed water was a sign of God’s blessing and covenantal loyalty to humanity. It was also one of the first signs to show that the Lord is God and there is no other.
God being the master teacher that he is, it is no wonder so many things foreshadow his work in Jesus Christ.