Bede

And it happened from that day on, that half of the young men did the work, etc. It is to be noted that not only half of the young men did the work and the other half were prepared for war, but even those who did the work, the youths, were girded with swords. For so great is the cunning of the ancient enemy, so great is the fury of his militia fighting against the Church, that not only the preachers of truth, but also the people of God themselves must always be vigilant against his schemes and stand as if in battle array. …

Commentary on Ezra and Nehemiah ↗