The four gospels in the New Testament approach the life of Christ from different points of view with different audiences in mind. The Gospel of John is especially unique in the approach it takes. Huntsman, an associate professor of ancient scripture at BYU, traced the symbolism of blood and water in John's writings.
Blood is symbolic of mortality. It is what nourishes earthly bodies (see Genesis 9:4).
Water is symbolic of eternal life. It represents the spiritual.
The first birth is one of flesh and blood. The second birth is water and spirit (John 3:3-5).
"The correlation of blood with mortality on the one hand and water with spiritual — even divine or eternal — life on the other can be consistently applied throughout John," Huntsman wrote.