Assigning numerical values to letters yields infinite interpretations.
Reprinted with permission from The Jewish Religion: A Companion, published by Oxford University Press.
Gematria is the exegetical method by which a word is equated with a different word because the two words have the same numerical value. Gematria is derived from the Greek and its resemblance to the word geometry has often been noted, but scholars are now uncertain of this etymology.
Application of Gematria
An illustration of how gematria operates can be given from comments on Jacob's dream of a ladder set on the ground with its top reaching to heaven (Genesis 28:12). The Hebrew word for "ladder," sulam, is formed from the letters samekh, lamed, mem. Since the Hebrew letters also serve as numerals, the total of sulam is 130, i.e. samekh (60) + lamed (30) + mem (40) = 130. Now the Hebrew word for "Sinai," also has the numerical value of 130, i.e. samekh (60) + yud (10) + nun (50) + yud (10) = 130. Hence, one interpretation of Jacob's ladder is that it represents the giving of the Torah on Mount Sinai and the "angels" who ascend and descend are Moses and Aaron.
In another interpretation, it is noted that the word for "money," mamon, has the numerical value of 136, i.e. mem (40) + mem (40) + vav (6) + nun (50) = 136 and if sulam is spelled in full, as it can be, with a vav, it also has the numerical value of 136, yielding the thought that wealth can drag a man down if acquired dishonestly but can reach to the very heavens if used for charitable purposes. The artificial nature of the exercise is readily admitted even by those who follow it, the adding of the vav in one interpretation and its omission in the other; and mamon is a post-biblical word for "wealth."
The possibilities of gematria are endless. To give just one further example, the Hebrew word for "wine," yayyin, has the same numerical value as the word sod, "secret," yielding the thought that when a man is in his cups there is a risk that his secret thoughts will be revealed.
Even in matters of halakhah the talmudic Rabbis resort at times to gematria. For instance, in the biblical account of the Nazirite vow the word yiheyeh, "he shall be" is used (Numbers 6: 5). This word has the numerical value of 30, i.e. yod (10) + hey (5) + yod (10) + hey (5) = 30. Thus the Rabbis say that if a man undertakes to be a Nazarite without specifying for how long a period, he is to be a Nazarite for 30 days. Here, however, it is highly likely that the gematria is not used as an actual derivation but as a peg on which to hang a law established on other grounds, that thirty days, for instance, is a reasonable minimum period where there has been no actual specification.