from thirty to fifty years old who came to do the work of serving and carrying the Tent of Meeting.
KJV
From thirty years old and upward even unto fifty years old, every one that came to do the service of the ministry, and the service of the burden in the tabernacle of the congregation,
ASV
from thirty years old and upward even unto fifty years old, every one that entered in to do the work of service, and the work of bearing burdens in the tent of meeting,