The Meaning of Numbers: The Number 18
The significance of the number eighteen in the Bible comes from its symbolic meaning for bondage. After taking possession of the promised land, the children of Israel were in bondage to several nations and peoples before Saul was made king. Two of their enemies, Eglon the Moabite king and the Philistines (with the help of the people of Ammon) oppressed them for 18 years (Judges 3:12, 14, 10:7 - 8). God freed the Israelites from Eglon through Ehud (who would become one of Israel's judges). He used Jephthah in the East and Samson in the South and West to free his people from the Ammonites and Philistines.
Bondage, however, can also be spiritual in nature. Jesus healed many demonically possessed or influenced people during his ministry. On one particular Sabbath, while teaching in a Synagogue, Jesus healed a woman that had a 'spirit of infirmity' which had bent her over for 18 years!
Appearances of the number eighteen
Joshua led the children of Israel into the promised land after the death of Moses. Seven years later, in 1398 B.C., he completes the dividing of Canaan among the Israelites. For the next 18 years, until his death at the age of 110, he serves as Israel's first Judge.
In the period preceding Israel's first human king (1398 to 1050 B.C.), a total number of 18 people served as Judges. They were Joshua, Othniel, Ehud, Deborah, Barak, Eli, Gideon, Abimelech, Tola, Jephthah, Samson, Samuel, Ibzan, Jair, Elon, Abdon and Samuel's two sons Joel and Abiah.