Israel Regardie

"The letters יהוה YHVH of the Tetragrammaton are used to imply the whole gamut of the four elements. י Y as the creative function of the Archetypal Realm, is Fire the Chiah; the first ה H represents the Cup, the symbol of the passive character of the Creative World, and is Water the Neschamah; ו V is the Son, the active vice-regent of the Father, and is Air the Ruach; and the final H ה is the Nephesch; the passive receptive Earth, fructifying all things."

"The Holy Spirit or the Shechinah, as we have already observed, is symbolized by the letter ש Shin. When, therefore, a man has invoked the Spiritual Self, his Holy Guardian Angel, and attained to His Knowledge and Conversation, the process is described as the descent of the letter ש Shin into the midst of the elemental name of יהוה Tetragrammaton, thus forming a new word יהשוה Yeheshua, the Pentagrammaton, the symbol of a new being, the Adept or Tsaddik in whom the birth of Spirit has equilibrized the base and unredeemed elements of matter."