With the passage of time, the numbers of the Kohanim greatly increased, and it became necessary for King David to further divide them into 24 shifts; each shift serving in the Temple two one-week shifts a year.

Additionally, each of the shifts was divided into seven smaller family groups, each group eligible to serve one day of that week. Every day there were four lotteries to determine the lucky Kohanim who would actually serve that day. 

The first lottery selected the kohein who would remove the ashes from the altar and prepare it for the day’s service. The second determined the thirteen Kohanim who would participate in the daily service of claring the Menorah, claring the golden altar, preparing, slaughtering, and transporting the morning and afternoon public sacrifices to the ramp of the altar. The third chose the Kohen who would offer the incense. The final lottery picked the Kohen who would take the limbs of the abovementioned sacrifices and put them onto the actual altar.¹

During the festivals, when Jerusalem was flooded with pilgrims and their sacrifices, all the Kohanim served together.

Any Kohen who wished to offer his own sacrifice on the altar was permitted to do so any day of the year.