Es el Principe de Paz!
Why is water into wine not acceptable, why does it need to be "the" water? Thank you
"el agua" points to a specific pool of water. It's just how this sentence is built.
"¡Él convirtió agua en vino!" is "He converted water into wine!"
why do you need the article "el" before agua?
Because it's "the water", not just any water.