The Meaning of Numbers: The Number 24
The number 24 is associated with the priesthood. Since it is composed of a multiple of 12, it takes on some of 12's meaning (which is God's power and authority, as well as perfect foundation) except in a higher form. Twenty-four, therefore, is also connected with the worship of God, especially at the temple.
It was King David who divided those responsible for the music in temple services, those who served as priests, and the Levites who aided the priests, into 24 courses (1Chronicles 23 - 24). When a particular course of priests served they usually divided their work amongst themselves by lot.
The order which the 24 courses of priests served in the temple are: 1) Jehoiarib; 2) Jedaiah; 3) Harim; 4) Seorim; 5) Malchijah; 6) Mijamin; 7) Hakkoz; 8) Abijah; 9) Jeshua; 10) Shecaniah; 11) Eliashib; 12) Jakim; 13) Huppah; 14) Jeshebeab; 15) Bilgah; 16) Immer; 17) Hezir; 18) Happizzez; 19) Pethahiah; 20) Jehezkel; 21) Jachin; 22) Gamul; 23) Delaiah; 24) Maaziah (1Chronicles 24).
The New Testament makes reference to one of the priestly courses when it states that the father of John the Baptist was a priest who served in Abia's (Abijah's) course (Luke 1:5). Abijah's course was the eighth one that rotated responsibilities with other priests.
Appearances of the number twenty-four
Although the book of Luke only has twenty-four chapters, it has more words the Acts, which has 28 chapters. Therefore, in a real sense, it is correct to say that Luke is the longest New Testament book.