His word prevailed against Joab, wherefore Joab departed, and went throughout all Israel, and came to Jerusalem. This brief general statement indicates a long and laborious task, simplified and facilitated in some measure by the primitive organisation of society and by rough and ready methods adopted to secure the very moderate degree of accuracy with which an ancient Eastern sovereign would be contented. When Xerxes wished to ascertain the number of the vast army with which he set out to invade Greece, his officers packed ten thousand men into as small a space as possible and built a wall round them; then they turned them out, and packed the space again and again; and so in time they ascertained how many tens of thousands of men there were in the army. Joab’s methods would be different, but perhaps not much more exact. He would probably learn from the “heads of fathers’ houses” the number of fighting men in each family. Where the hereditary chiefs of a district were indifferent, he might make some rough estimate of his own. We may be sure that both Joab and the local authorities would be careful to err on the safe side. The king was anxious to learn that he possessed a large number of subjects. Probably as the officers of Xerxes went on with their counting they omitted to pack the measured area as closely as they did at first; they might allow eight or nine thousand to pass for ten thousand. Similarly David’s servants would, to say the least, be anxious not to underestimate the number of his subjects. The work apparently went on smoothly; nothing is said that indicates any popular objection or resistance to the census; the process of enumeration was not interrupted by any token of Divine displeasure against the “cause of guilt unto Israel.” Nevertheless Joab’s misgivings were not set at rest; he did what he could to limit the range of the census and to withdraw at least two of the tribes from the impending outbreak of Divine wrath. The tribe of Levi would be exempt from taxation and the obligation of military service; Joab could omit them without rendering his statistics less useful for military and financial purposes. In not including the Levites in the general census of Israel, Joab was following the precedent set by the numbering in the wilderness.