One of the rabbinic methods used by Jewish teachers for interpreting the Old Testament. It involved analyzing words based on the numerical value of their letters or rearranging letters according to a specific system. For example, some rabbis have argued that Eliezer (Genesis 15:2) represented all of Abraham's servants combined because Eliezer's name equals 318, which was the number of Abraham’s servants (Genesis 14:14). Another example is how the name "Babylon" is derived in Jeremiah 25:26 and 51:41 by changing the last letter of the Hebrew word for Babylon to the first letter of the same word.
In the pseudepigraphal Epistle of Barnabas, the 318 servants of Abraham (Genesis 14:14) are seen as symbolizing Jesus's death on the cross. This interpretation is based on the Greek letter Tau, or "t," which has a numerical value of 300 and is cross-shaped, and 18, which corresponds to the first two letters of the Greek word for Jesus.
In the book of Revelation, the number of the beast is 666 (Revelation 13:18). In biblical symbolism, the number seven is considered perfect, and three sevens represent complete perfection. Thus, 666 is seen as falling short of this perfection.