We have, here, the sum total at the foot of the account. They were, in all, 600,000 fighting men, and 3,550 over. Some think that, when this was their number some months before (Exodus 38.26), the Levites were reckoned with them but, now that tribe was separated for the service of God, yet so many more had, by this time, attained to the age of twenty years, as that, still, they were the same number, to show that, whatever we part with for the honor and service of God, it shall certainly be made up to us, one way or another.
Now, we see what a vast body of men they were. Let us consider (1) how much went to maintain all these (besides twice as many more, no question, of women and children, sick and aged, and the mixed multitude) for forty years together in the wilderness. And they were all at God’s finding every day, having their food from the dew of heaven and not from the fatness of the earth. O, what a great and good housekeeper is our God, who has such numbers depending on Him and receiving from Him every day!
(2) What work sin makes with a people. Within forty years, most of them would indeed have died, of course, for the common sin of mankind for, when sin entered the world, death came with it, and how great are the desolations which it makes in the earth! But, for the particular sin of unbelief and murmuring, all those who were now numbered, except two, laid their bones under their iniquity and perished in the wilderness.
(3) What a great multitude God’s spiritual Israel will amount to at last, though, at one time and in one place, they seem to be but a little flock. Yet, when they come all together, they shall be a great multitude, innumerable (Revelation 7.9). And, though the church’s beginning be small, its latter end shall greatly increase. A little one shall become a thousand. – Matthew Henry (1662-1714). Comment at Numbers 1.44-46.