The Ari Hakadosh said that we must understand the significance of the 12 challos (special breadS of shabbos). When we eat on Shabbos, we ingest kedusha (holiness) from the highest worlds. The first two letters in the name of G-d embody a kedusha (holiness) that is beyond our comprehension and the second two letters transform this kedusha into a digestible form. The letter yud (tenth letter of the Hebrew alphabet) symbolizes G-d’s concealment from this world. The letter vov (sixth letter of the Hebrew alphabet) symbolizes a weakened level of kedusha. The letter Hey symbolizes G-d’s expansiveness and revelation to the world. We can only experience kedusha when it is first concealed, and then delicately drawn out of concealment.