Numbers 4:3

3. From thirty years old The minimum limit is fixed at ten years above the military age. This is not surprising when we consider that the sacred service required not only physical strength, but especially intellectual maturity and sound judgment. These are rarely found at twenty, but at thirty the character becomes fixed, and the mind assumes the oaken toughness of manhood. John the Baptist began to preach when thirty. Jesus Christ, though not under the limitations of the Levite, did not enter upon his public mission till thirty years of age. Although the world was in sad need of the Gospel when he was twenty, he waited until he could present to the wondering world a perfect manhood enshrining the Supreme Godhead. Hence the celebrated Hebraist and theologian, Prof. Moses Stuart, has very ably argued, that as a general rule none should be ordained to the responsible office of the ministry of the Gospel till thirty years of age. For a discussion of the discrepancy between the thirty years required here and the twenty-five years in Numbers 8:24-25, see general remarks at the close of this chapter.

Until fifty years This is a few years above the usual maximum military age. In ancient Rome this was at forty-six; in the United States a man at forty-five is exempt. The reason for the continuance of the Levite beyond the military age-limit of many nations is, that the intellect and judgment at that age have suffered no deterioration.

All that enter into the host Hebrew, Every one that enters the army. The service of God is a spiritual warfare; the body of believers constitutes the militant Church. Hence the frequency of martial metaphors in St. Paul’s epistles.