The Meaning of Numbers: The Number 20
The number twenty (20), which is one more than nineteen, is twice ten. It can convey a meaning of a complete or perfect waiting period.
Jacob, for 20 years, waited to get possession of his wives and property, and to be freed from the control of Laban his father-in-law (Genesis 31:38 - 41). The children of Israel, for 20 years, waited to be freed of Jabin, king of Canaan, who oppressed them. God response was to raise up Deborah and Barak, who freed the people from bondage (Judges 4 - 5).
The Philistines, in the days of Samuel the prophet, battled and overcame Israel, taking the Ark of the Covenant back to their land. The Ark brought such calamities on the Philistines that after seven months they gave it back to the Israelites. It ended up in the city of Kirjath-jearim that is several miles west of Jerusalem. Israel had to wait at least twenty years (1Samuel 5 - 7) before the Ark would be moved again.
Appearances of the number twenty
Several Scriptural chapters contain exactly 20 verses in the King James translation. These include Judges 15 and 16, six of the Psalms (9, 49, 66, 72, 77 and 147), Revelation 1 and 14, along with many others.
Solomon spent seven years building the house of God in Jerusalem and another 13 building his own home for a total number of 20 years. After he had completed both buildings Solomon gave Hiram, the king of Tyre, twenty cities in the land of Galilee (1Kings 9:10 - 11).
Number 20 and sleep
The Scriptures record at least 20 separate messages conveyed while a person is sleeping. God, through a dream, warned Abimelech not to go near Abraham's wife (verse 3 of Genesis 20). Jacob dreams of a ladder to heaven (28:12) and is told in a second one to leave his employer (31:10).
Jacob's employer Laban is warned, in a dream, to leave the patriarch alone (Genesis 31:24). Joseph dreamt his brothers bowed before him (Genesis 37:5) then dreamt his parents would do the same (verse 9). A butler and a baker, in an Egyptian prison, dream what their fates will be (Genesis 40).
The Egyptian Pharaoh is informed two different times, while he is sleeping, about the country's food stores over the next fourteen years (Genesis 41). A person in the Midianite army dreams of Gideon conquered his people (Judges 7).
King Solomon, while sleeping, is offered by God anything he wants (1Kings 3:5). Babylon's king has it revealed to him all the world empires to exist until Christ's return (Daniel 2:3) and his punishment for being so vain (Daniel 4). Daniel is also told while he sleeps about four great world empires (Daniel 7).
Only five dreams are mentioned in the New Testament. Three of them occur to Joseph, Jesus' stepfather, regarding the birth of Christ and protecting the young child from Herod the Great's wrath. The Parthian Magi are informed by a dream to not visit Herod on their travel home (Matthew 2:12) and Pilate's wife receives a troubling dream warning that her husband should not do anything to harm Jesus (Matthew 27:19).
Additional info on Biblical Meaning of 20
Exodus 20 delineates God giving the Ten Commandments to the children of Israel. This chapter in the Bible is reference twice by the Gospel of Mark (Mark 7:10 and 10:19), six times by Matthew (Matthew 5:21, 27, 33, 15:4, 19:18 - 19, 22:39) and once by Luke (Luke 18:20).
God promised Abraham that if he found only twenty righteous people in Sodom and Gomorrah he would not destroy both cities (Genesis 18:31).
Samson was Judge over Israel twenty years (Judges 16:31).
The book of Hebrews uses over 20 different names and titles for Jesus Christ.