Zedekiah was twenty-one years old when he became king, and he reigned in Jerusalem eleven years.

2 Kings 24:18
Zedekiah was twenty-one years old when he became king, and he reigned in Jerusalem eleven years. His mother's name was Hamutal daughter of Jeremiah; she was from Libnah.

Jeremiah 1:3
and through the days of Jehoiakim son of Josiah king of Judah, until the fifth month of the eleventh year of Zedekiah son of Josiah king of Judah, when the people of Jerusalem went into exile.

Jeremiah 27:1
At the beginning of the reign of Zedekiah son of Josiah king of Judah, this word came to Jeremiah from the LORD.

Jeremiah 28:1
In the fifth month of that same year, the fourth year, near the beginning of the reign of King Zedekiah of Judah, the prophet Hananiah son of Azzur, who was from Gibeon, said to me in the house of the LORD in the presence of the priests and all the people:

Jeremiah 34:2
The LORD, the God of Israel, told Jeremiah to go and speak to Zedekiah king of Judah and tell him that this is what the LORD says: "Behold, I am about to deliver this city into the hand of the king of Babylon, and he will burn it down.

Jeremiah 52:1
Zedekiah was twenty-one years old when he became king, and he reigned in Jerusalem eleven years. His mother's name was Hamutal daughter of Jeremiah; she was from Libnah.

Zedekiah was one and twenty years old when he began to reign, and reigned eleven years in Jerusalem.