Page "Kohen" Paragraph 6

When the First and Second Temples were built, the priests assumed these same roles in these permanent structures on the Temple Mount in Jerusalem.

They were divided into 24 groups, each group consisting of six priestly families.

Each of the 24 served for one complete week, with each of the six serving one day per week, on the Sabbath all six worked in tandem.

According to later rabbinical interpretation these 24 groups changed every Sabbath at the completion of the Mussaf service.

On the biblical festivals all 24 were present in the Temple for duty.