Depending on the context, numbers are used in the Bible to symbolize concepts such as completeness, sanctity and organization. However, not all Christians support the idea of using numbers to extract additional spiritual significance.
Bible numerologists agree that the number one is symbolic of unity. An example is found in John 17:21, where Jesus expresses the hope that his followers "may all be one." Also, the number one is emphasized in the Old Testament, particularly in Deuteronomy 6:4, which reads, "Hear, O Israel: The Lord our God, the Lord is one."
The number 12 also occurs frequently in the Bible; numerologists interpret this number as a symbol of perfection or completeness. The most prominent example of this connection is Jesus' selection of 12 men to become his apostles. Other notable examples of this number's usage in the Bible include the 12 tribes of Israel and the 12 foundation stones of New Jerusalem as described in Revelation 21. Multiples of 12, such as the 144,000 holy ones mentioned in Revelation 7, are thought to have a similar meaning.
The number six has a negative connotation in the Bible, usually referring to something imperfect or incomplete. One prominent example is found in Revelation 13:18, where the number 666 is described as "the number of man." Six is probably used as a symbol of imperfection because seven is used a symbol of perfection, similar to the number 12. Examples of this symbolism include the seven marches around Jericho on the seventh day, the seven pairs of clean animals that Noah brought into the ark and the seven seals of Revelation.