Rudolf Steiner:
Now I must tell you something which, though easy to understand intellectually, is difficult for the man of today to grasp with his whole soul. The time when the gospels were written was the dawn of Christianity. One used names then in a way which I will now explain. One did not look to the outer physical man, but one saw something higher, the spiritual, shining through it. A name was not used as it is today, it had a significance. Suppose someone was called James (Jacobus). James really means water. Water is the spiritual scientific term for the soul element. If I call somebody James, I say that his soul shines through his body. With this, I signify that he belongs to the watery element. If I give the name James to an initiate, he is to me the symbol for water (Hebrew — Jam). James is nothing but the technical name for an initiate who especially governs the force of water in its occult sense.
Thus were the three disciples who were taken up to Mount Tabor called by their initiate names: James means water, Peter stands for earth, or rock (Hebrew — Jabascha), John signifies air (Ruach). Thus, John means he who has attained the higher self. This leads us deep into the secret doctrines. Transport yourself back into the time when man only possessed the lower principles — the third Root Race, the Lemurian epoch. Mankind did not then breathe air, he breathed through gills. Lungs and breathing through lungs developed later. This process coincided with the impregnation by the higher self. Air is, according to the hermetic principle, the lower which represents the higher — the higher self. If I call somebody John (Johannes), then he is one who has awakened his higher self, who governs the occult forces of air. Jesus is the one who governs the occult forces of fire (Nur). Thus you have in these four names the representatives of earth, water, air, and fire. They are the names of the four who ascended Mount Tabor.
Jam : Water — James
Nur : Fire — Jesus
Ruach : Air — John
Jabascha : Earth — Peter
Think of these four together on the Mount of Transfiguration. There you have at the same time the initiates who govern the four elements: fire, water, air, and earth. What happened? It was made manifest spiritually that through the appearance of Jesus the whole power of the elements was renewed in such a way that the life pulsing through the elements passed through a new, important phase of its development. This is the transfiguration seen occultly. If somebody goes through the transfiguration in this manner, if he has within himself the stages of water, earth, and air, and even rises to the forces of fire, then he is a reawakened one, someone who has gone through the crucifixion. Thus in the case of the other evangelists this scene is but a preparation for the deeper initiation scene of the crucifixion itself. In the John Gospel, everything is already prepared. The preparatory scene does not appear, only the death on the Mount of Golgotha. Jam, Nur, Ruach, Jabascha — INRI — this is the meaning of the words on the cross.