Twenty-six is, in Jewish tradition, the number of the divine Name itself. The four letters of the Tetragrammaton, yod-he-vav-he, carry the gematria values ten, five, six and five, which total twenty-six, so the number stands for the ineffable Name that is written but not pronounced. This makes twenty-six one of the most charged numbers in Kabbalistic arithmetic, and commentators find it woven through the text: the count of generations from Adam to Moses, at whose hand the Name was revealed, is reckoned as twenty-six in some traditional schemes. As with chai for eighteen, the significance is produced entirely by the letter-values of a word rather than by counting objects, which is the essence of gematria and the reason the technique could find meaning almost anywhere.
Cheiro's 1926 Book of Numbers reads twenty-six as an unfortunate compound, warning of loss brought about by misplaced trust in others rather than by the querent's own error, a reading Florence Campbell's 1931 book and Juno Jordan's 1965 systematisation both carried forward into the standard American chart; the reading sits in an odd tension with the number's Hebrew gematria as the value of the Tetragrammaton already described, since the two traditions, an American commercial numerology and Jewish mystical arithmetic, arrived at their very different readings of the same number by entirely unrelated routes.