Passing the river

Passing the River, or Transitus Fluvii (lat.) is a Hebraic Kabbalistic writing system derived from the ancient Hebrew alphabet. The "river" is referred to in the Torah (Isaiah 11:15-16) as the Euphrates River. In the mystical Kabbalah the Euphrates River is symbolic of the sephira Binah in the tree of life . Binah is derived from the Hebrew root (bein) meaning "between" and is often referred to as a river. In "Passing the River" the Kabbalist is believed to have achieved the edge "between" the uppermost supernal triad and the lower sephiroth on the tree of life in Kabbalah. This writing system was designed to enable Kabbalists to reveal or conceal teachings; and served as a type and rite of passage. The Hebrew patriarch Abraham is said to have been entrusted with this alphabet.
It is often used in modern Wicca and forms of Witchcraft to hide magical writings such as the contents within one's Book of Shadows from others.