Numbers 4:39
From thirty years old and upward even unto fifty years old, every one that entereth into the service, for the work in the tabernacle of the congregation,
Cross-reference
Numbers 4:35
Parallel
Numbers 4:35 uses the identical age formula (30–50) for the Kohathites. Both verses share the same criterion for tabernacle service.
Luke 3:23
Typology
Luke 3:23 notes Jesus was about 30 at his ministry's start — the same age Levites here began their tabernacle service.