*Minor differences ignored. Grouped by changes, with first version listed as example.
As the Lord commanded Moses,.... In this Moses and David differed in numbering the people of Israel; the one did it by an express command from God, and in obedience to it; the other without one, and against his will, 1-Chronicles 21:17,
so he numbered them in the wilderness of Sinai; where they now were when this order was given, Numbers 1:1; and from whence they removed the twentieth day of this month, Numbers 10:11; so that in less than three weeks time, perhaps much sooner, this affair was finished; and it may be, that the place of numbering them at this time is expressly observed, to distinguish it from another numbering of them, recorded in this book, which was done in the plains of Moab, Numbers 26:2.
As the Lord commanded Moses, &c.--The numbering of the people was not an act sinful in itself, as Moses did it by divine appointment; but David incurred guilt by doing it without the authority of God. (See on 2-Samuel 24:10).
He numbered them - For ought that appears in one day.
*More commentary available at chapter level.