The number 400,000 appears in the Bible as a large military figure, associated with the combined strength of the tribes of Israel and with vast armies at war.
In Judges 20:2 and 20:17, 400,000 foot soldiers are mentioned who gathered from the tribes of Israel for the internal war against the tribe of Benjamin after the assault at Gibeah. The number here expresses the combined strength and unity of all Israel as they acted collectively against wrongdoing within their own ranks. In 2 Chronicles 13:3, King Abijah of Judah lines up with 400,000 chosen warriors against Jeroboam's 800,000 men from the Northern Kingdom—a conflict in which God grants victory to the numerically inferior side. In both contexts, the number serves as an expression of massive yet still limited military power, and it underscores the seriousness of the biblical confrontations in which it appears. The number 400,000 can be seen as a combination of 400 and 1,000. The number 400 may symbolize a long period of testing (cf. the 400 years in Egypt, Genesis 15:13), while 1,000 is often used as a symbol of completeness or an overwhelming multitude. Nevertheless, this combination has no deeply established mystical meaning beyond its biblical context. The large numbers in Judges 20 and 2 Chronicles 13 have been the subject of debate among scholars. The Hebrew word "elef" (אֶלֶף) can mean both "thousand" and "military unit" or "clan," which suggests that the actual forces may have been significantly smaller than a literal reading implies.*