1 Chronicles 6:48

“This is what is assigned to the Levites: from twenty-five years old and upward they shall go in to wait on the service in the work of the Tent of Meeting;

Of the Izharites, Chenaniah and his sons were for the outward business over Israel, for officers and judges.

These were the sons of Levi after their fathers’ houses, even the heads of the fathers’ houses of those who were counted individually, in the number of names by their polls, who did the work for the service of Yahweh’s house, from twenty years old and upward.

Moreover in Jerusalem Jehoshaphat appointed Levites and priests, and of the heads of the fathers’ households of Israel, for the judgment of Yahweh, and for controversies. They returned to Jerusalem.

“ ‘ “In a controversy they shall stand to judge. They shall judge it according to my ordinances. They shall keep my laws and my statutes in all my appointed feasts. They shall make my Sabbaths holy.

you shall count them from thirty years old and upward until fifty years old: all who enter in to wait on the service, to do the work in the Tent of Meeting.

from thirty years old and upward even to fifty years old, everyone who entered in to do the work of service and the work of bearing burdens in the Tent of Meeting,

You shall make judges and officers in all your gates, which Yahweh your God gives you, according to your tribes; and they shall judge the people with righteous judgment.

Now in the thirtieth year, in the fourth month, in the fifth day of the month, as I was among the captives by the river Chebar, the heavens were opened, and I saw visions of God.

Joseph was thirty years old when he stood before Pharaoh king of Egypt. Joseph went out from the presence of Pharaoh, and went throughout all the land of Egypt.

If the thief isn’t found, then the master of the house shall come near to God, to find out whether or not he has put his hand on his neighbor’s goods.

from thirty years old and upward even until fifty years old, all who enter into the service to do the work in the Tent of Meeting.

you shall count them from thirty years old and upward even to fifty years old—everyone who enters on the service, to do the work of the Tent of Meeting.

from thirty years old and upward even to fifty years old, everyone who entered into the service for work in the Tent of Meeting.

Is it a small thing to you that the God of Israel has separated you from the congregation of Israel, to bring you near to himself, to do the service of Yahweh’s tabernacle, and to stand before the congregation to minister to them;

Joshua called for all Israel, for their elders and for their heads, and for their judges and for their officers, and said to them, “I am old and well advanced in years.

Joshua gathered all the tribes of Israel to Shechem, and called for the elders of Israel, for their heads, for their judges, and for their officers; and they presented themselves before God.

David consulted with the captains of thousands and of hundreds, even with every leader.

He gathered together all the princes of Israel, with the priests and the Levites.

David said, “Of these, twenty-four thousand were to oversee the work of Yahweh’s house, six thousand were officers and judges,

For their office was to wait on the sons of Aaron for the service of Yahweh’s house, in the courts, and in the rooms, and in the purifying of all holy things, even the work of the service of God’s house;

Moreover, David and the captains of the army set apart for the service certain of the sons of Asaph, and of Heman, and of Jeduthun, who were to prophesy with harps, with stringed instruments, and with cymbals. The number of those who did the work according to their service was:

David assembled all the princes of Israel, the princes of the tribes, the captains of the companies who served the king by division, the captains of thousands, the captains of hundreds, and the rulers over all the substance and possessions of the king and of his sons, with the officers and the mighty men, even all the mighty men of valor, to Jerusalem.

and those who were listed by genealogy of the priests by their fathers’ houses, and the Levites from twenty years old and upward, in their offices by their divisions;

Now in the second year of their coming to God’s house at Jerusalem, in the second month, Zerubbabel the son of Shealtiel, and Jeshua the son of Jozadak, and the rest of their brothers the priests and the Levites, and all those who had come out of the captivity to Jerusalem, began the work and appointed the Levites, from twenty years old and upward, to have the oversight of the work of Yahweh’s house.

You, Ezra, according to the wisdom of your God that is in your hand, appoint magistrates and judges, who may judge all the people who are beyond the River, who all know the laws of your God; and teach him who doesn’t know them.

After him, the Levites, Rehum the son of Bani made repairs. Next to him, Hashabiah, the ruler of half the district of Keilah, made repairs for his district.

Joel the son of Zichri was their overseer; and Judah the son of Hassenuah was second over the city.

The overseer also of the Levites at Jerusalem was Uzzi the son of Bani, the son of Hashabiah, the son of Mattaniah, the son of Mica, of the sons of Asaph, the singers, over the business of God’s house.

For the priest’s lips should keep knowledge, and they should seek the law at his mouth; for he is the messenger of Yahweh of Armies.

Jesus himself, when he began to teach, was about thirty years old, being the son (as was supposed) of Joseph, the son of Heli,

Take heed, therefore, to yourselves, and to all the flock, in which the Holy Spirit has made you overseers, to shepherd the assembly of the Lord and God which he purchased with his own blood.

I commit this instruction to you, my child Timothy, according to the prophecies which were given to you before, that by them you may wage the good warfare,

This is a faithful saying: someone who seeks to be an overseer desires a good work.

not a new convert, lest being puffed up he fall into the same condemnation as the devil.