This idea is a persistent one across cultures. Water's flow also denotes the transmission of wisdom from a higher plane to ours. Water is also a domain of the deepest emotions, passions, overwhelming feelings. In Celtic legend, the Well of Wisdom is the spiritual source of everything, particularly the streams of the five senses. Celtic wells also were viewed as the entrances to the womb of the earth mother, from which all life flows.
Water is a purifier, both of body and of soul.
The ritual of baptism carries within it the sense of returning to the medium of birth, of being purified, and of being reborn. This is not a new idea. Death was, for the soul, to become as water. One idea was that the souls of the dead incline towards water because they wish to be reincarnated. The British Isles contain thousands of wells and springs at which people throughout history have prayed for miracles, cures, and fertility.