What does the Bible say about the number thirteen?
Interestingly, there are thirteen passages that mention the specific number thirteen. There does not seem to be any significance to the number in the Bible, except as a number. Several times it is mentioned as the number of cities some of the families of the Levites got within other tribes' territories (5 times in Joshua, twice in 1 Chronicles); the Levites didn't get a territory of their own. Once it is mentioned as an age (Genesis 17:25). Another time it is the number of brothers and sons an individual had (1 Chronicles 26:17). It is the number of years Solomon took to build his palace (1 Kings 7:1). Ezekiel describes a gate that was thirteen cubits long (Ezekiel 40:11). And it was the number of young bulls offered on the first day of Succoth (the Feast of Booths) (Numbers 29:13-14). The number of bulls was reduced by one each day of the feast, down to seven.
Again, it doesn't appear that the number thirteen has any special significance in the Bible. The superstitions about the number are probably related to the Last Supper of Jesus, which Jesus and the twelve apostles shared. The New Testament, however, makes no mention of the number thirteen.