Since there were Temple officials and spiritual leaders among the descendants of both Eleazar and Ithamar, assignments were made by drawing lots.

The descendants of Eleazar and of Ithamar took turns drawing lots. Then they were registered by Shemaiah son of Nethanel, a Levite secretary. The king, his officials, the priest Zadok, Ahimelech son of Abiathar, and the heads of the priestly families and of the Levite families, were all witnesses.

(SEE 26:54)

To determine the assignment of duties they all drew lots, whether they were young or old, experts or beginners.

Each family, regardless of size, drew lots to see which gate it would be responsible for.