65. Rabbi Shimon said: The secret of these seven Zayins - THE THREE ZAYINS IN THE THREE HEADED SHIN AND THE FOUR ZAYINS IN THE FOUR HEADED SHIN - that are inscribed on the Tefilin, is that the Zayins in the Shins INSCRIBED ON BOTH SIDES OF THE TEFILIN allude to the seven lobes in man's lung, by which he draws air and exhales with it a fiery spark from his mouth - BECAUSE AIR IS COMPOSED OF FIRE, WATER AND AIR. They also allude to the seven days OF THE WEEK and the SEVEN weeks from Pesach to Shavuot. Also, they indicate the seven branches of the candelabra, on which there are seven holy lamps. They also indicate the seven planets that shine in the firmament and they indicate the seven grades - CHESED, GVURAH, TIFERET, NETZACH, HOD, YESOD AND MALCHUT - by which the world is maintained, which are the foundation, root and essence of everything. The friends said about these SEVEN ZAYINS that whoever wishes to put on the head Tefilin has to examine these two Shins hinted in the seven Zayins, for there are an allusion in them to hidden mysteries and deep allusions.