The Meaning of Numbers: The Number 30
Part of the meaning of the number 30 comes from it symbolizing dedication to a particular task or calling. Aaronic priests were initially dedicated to serving at thirty years of age (Numbers 4:3). God likely choose this age because it was when a person reached both physical and mental maturity and could therefore handle major responsibilities.
John the Baptist, who was of priestly descent (his mother was a descendant of the daughters of Aaron and his father was a priest), began his ministry at age 30. In the fall of 26 A.D., at the age of thirty, Christ began to publicly preach the gospel (Luke 3:23). His ministry lasted for three and one-half years.
This number can also represent the sacrificial blood of Jesus, as He was betrayed by Judas for thirty silver coins. This act was a fulfillment of prophecy (Zechariah 11:12). When Judas flung the 'blood money' he was paid back into the temple, the priests did not accept it as an offering but rather decided to buy a potter's field with it. Though they were not aware of it, what they did was also fulfilling prophecy (verse 13).
Jesus, in 30 A.D., suffered and shed His precious blood as God's sacrificial Lamb for the world's sins.
Appearances of the number thirty
The Dead Sea Scrolls were discovered in caves on the upper northwest shore of the Dead Sea started in 1947. Among all the scrolls found over the years, 30 copies of the Psalms have been identified.
The patriarchs Salah (grandson of Shem), Peleg (who lived to see the world's continents divide) and Serug (the great-grandfather of Abraham) had their first sons at the age of 30.
The prophet Ezekiel begins his book of the same name "in the 30th year" (which likely referenced his age at the time - Ezekiel 1:1). It is at this time he receives his first recorded vision from God, known as the "wheel in the middle of a wheel" or "wheel within a wheel" vision.
Abraham was promised that if God found at least thirty righteous people in Sodom and Gomorrah he would not destroy the cities (Genesis 18:30).
The number 30 and Israel's Judges
Jair, one of the Judges of Israel delineated in the Bible, had thirty sons. He was wealthy enough not only to provide each of them with their own horse to ride, but also gave each of them a city for 30 total (Judges 10:4). Ibzan, another Judge of Israel, had thirty sons and the same number of daughters (Judges 12:9).
Samson, a Judge of Israel from 1085 - 1065 B.C., offered a prize of thirty sheets and thirty change of garments to thirty men if they answered a riddle within a week (Judges 14:11 - 14).
Additional info on Biblical Meaning of 30
Joseph, a type of Jesus, was thirty years old when Egypt's Pharaoh placed him in charge over all that he ruled. King David also, when he began to reign over Israel, was this age (2Samuel 5:4).
Both the death of Aaron and Moses was mourned by the children of Israel for thirty days (Numbers 20:29, Deuteronomy 34:8).
In 30 A.D. the New Testament church is born. It started in Jerusalem on the day of Pentecost (Sunday, May 28) when God's spirit initially came upon 120 individuals celebrating the Feast day. Later in the day an additional 3,000 were baptized, received God's Holy Spirit, and became Christians (Acts 2).