Abarim Publications' online Biblical Greek Dictionary
The word επτα (hepta) is the cardinal number seven, but it needs to be remembered that the ancients did not live in an arithmetically accurate world such as ours. Most Greek numbers were actually words (such as our word επτα, hepta, meaning seven) and only rarely the Greeks wrote their numbers using single Greek letters to represent single numerical digits — see for instance the famous number 666 in Revelation 13:18, which is spelled χξς (chxs). But in each case, all Greek numbers looked like words and were mostly treated like words: fuzzy and subject to poetic license. This in turn meant that daily calculus was more of an art than science — the reason why young Asian children are usually better at calculus than their Western colleagues is that Asian languages represent numbers more consistently and more conductive of calculus than Western languages. When children learn to think in numbers, the advantage shrinks. And when Europeans adopted Arabic numerals, the Renaissance commenced.
Unless the context was clearly arithmetical (like: you owe me 2 bits for 4 apples), in Greek texts numbers came with a symbolic value that was similar to that of regular words, and were likewise subject to experience. An army of "ten-thousand men" may have actually consisted of 6754 enlisted troops but nobody cared about the number 6754 and only about the colossal threat this army posed. In our modern world, large round numbers still have the symbolic meaning of "a whole lot", but in the Greek world, smaller numbers too had meaning beyond their arithmetic nature. This has led many an aspiring prophet down the garden path of numerology, only to find that this garden path is rather steep, short and decidedly inanimate of termination. That's not to say that there's nothing there; it's just to indicate that even the meaning with which numbers are charged require a controlled, contained and inspired approach.
The Hebrew word for seven is שבעה (shib'a), which stems from a verb that means both "to be seven" and "to make an oath" (hence the name Elizabeth). It's also spelled identical to a verb that means to saturate (people with food or the earth with rain). Seven is the number of days in which God creates reality — because, no, the creation week is not the first week long ago but the grand super-structure of all evolution across all the ages; whatever evolves naturally, naturally evolves via seven stages (see for more our study of Genesis 1) — and by using the number seven, a Biblical author appears to mostly want to refer to the entirety of any natural cycle of growth or evolution that stands on any previous natural cycle of growth or evolution (hence the seven daughters of Jethro of Midian, Exodus 2:16; the seven pillar of wisdom, Proverbs 9:1; the seven deacons of the church, Acts 6:3; the seven churches of Asia Minor, Revelation 1:4; and so on).
Our word επτα (hepta) meaning seven occurs a whopping 89 times in the New Testament, see full concordance, and from it come:
- The cardinal number εβδομηκοντα (hebdomekonta), meaning seventy. Seventy is of course seven times ten, and the Greek word for ten is δεκα (deka). Our word εβδομηκοντα (hebdomekonta), meaning seventy is used 5 times in the New Testament, see full concordance, most strikingly as the "seventy" whom Jesus sent out into the towns he would visit (Luke 10:1, 10:17). In modern folklore, Jesus is often depicted as a kind of wandering sage with twelve adoring disciples, but his operation obviously far exceeded that. His funding came almost directly from the state treasury (Luke 8:3) and his later spokesman Paul was deemed important enough to actually be granted audience with the Caesar (Acts 25:12), who at that time ruled about 50 million people, all wanting to have a word with him. From our word in turn derives:
- The adverb εβδομηκοντακις (hebdomekontakis), meaning "seventily" (or "seventy times"; it's a word like "twice" which means "two times"). In the New Testament this word occurs only in Matthew 18:22, and in the Septuagint it only occurs in Genesis 4:24. These two instances are obviously related and their contexts each other's antithesis.
- The adjective εβδομος (ebdomos), which is the ordinal number seventh. This word is used 9 times; see full concordance.
- The adverb επτακις (heptakis), meaning "sevenly", or seven times. Like the number seven itself, this number appears to also refer to a wholly complete process. Someone who sins sevenly (Matthew 18:21) is basically leading the entire process of his life off the deep end and into perdition. Someone who sevenly does something wrong, simply is like that and will not ever change. Jesus' response of seventy times seven forgivenesses is not about numbers but about intensity. Someone who's entirely messed up can not be saved by counteracting every single failure with a corresponding remedy, but by massively overwhelming that person by the consistent application of a vastly more stable and fruitful lifestyle. This adverb is used 4 times; see full concordance.
- Together with the adjective χιλιοι (chilioi), meaning thousand: the cardinal number επτακισχιλιοι (heptakischilioi), meaning seven thousand (Romans 11:4 only).