And this light, which is very subtle, closed due to lack of mercy, was maintained and perfected in him by the middle line, the six extensions, which are the six letters of wisdom, which are not known, that is, they are not revealed to illuminate, except when the thin light of ABA and IMA is hidden, because then the very subtle light illuminates with its illumination. Explanation: Because the illumination of wisdom does not illuminate except at the point of the Shuruk at the time of the elevation of the three points, Holam, Shuruk and Hirik, one after the other, (as explained in Shlach, 39, "VeG") and at the moment when it illuminates the point of the Shuruk, the light of mercy of ABA and IMA is closed, (as explained above in Bereshit, 13, "UveTeda", and see in the introduction to the Book of Zohar, folio 17, "Kayema") it is found that the very subtle light illuminates only at the time of the concealment of the thin light.