John Calvin on Numbers 26:28-50

28. The sons of Joseph after their families. The comparison of the two tribes, which sprang from the same head, is worthy of notice. By the fact that Manasseh was the father of only one son, There appears to be an oversight here: see Joshua 17. the prophecy of Jacob, when he declared that the first-born should be inferior to his younger brother Ephraim, began already to receive its accomplishment. Nevertheless, God’s blessing extended far and wide for the increase of his family, so that they exceeded the tribe of Reuben in number. But further, though the larger number of children (πολυτεκνία) in which the descendants of Ephraim were superior, was a kind of type of his promised fecundity, still the excellency and dignity, of which Jacob prophesied, was deferred to a distant period; since in this respect the tribe of Ephraim was inferior by about a third, whereas a more numerous issue had been promised him. Although, therefore, God had not spoken in vain, yet the fulfillment of His promise did not immediately appear.

In the tribe of Dan, however, the incredible power of God was put forth. He was contemptible among his brethren; and thence it was an extraordinary blessing accorded to him in the shape of an honorable degree and name, when Jacob declares that “Dan shall judge his people.” (Genesis 49:16.) He is said to have begotten only one son; yet his posterity exceeds 64,000.