The sons of Simeon by their kindreds: Namuel, of him is the family of the Namuelites: Jamin, of him is the family of the Jaminites: Jachin, of him is the family of the Jachinites:

Sons of Simeon by their families: of Nemuel is the family of the Nemuelite; of Jamin the family of the Jaminite; of Jachin the family of the Jachinite;

The sons of Simeon, by their kinships: Nemuel, from him is the family of the Nemuelites; Jamin, from him is the family of the Jaminites; Jachin, from him is the family of the Jachinites;

Filii Simeon per familias suas: de Nemuel, familia Nemuelitarum: de Jamin, familia Jaminitarum: de Jachin, familia Jachinitarum:

The sons of Simeon, after their families,.... This tribe was next numbered, not only because Simeon was next to Reuben by birth, but because his tribe was under the standard of Reuben; two of his sons are a little differently named here than they are in Genesis 46:10, there the eldest is called Jemuel, here Nemuel; there the youngest but one is named Zohar, here Zerah; and one of them is here omitted, namely Ohad, perhaps because he died without children, and so no family sprang from him; wherefore the families of Simeon were but five, and the number of them were 22,200; by which it appears there was a very great decrease in this tribe since the last muster, even 37,100 which in some measure is to be accounted for by the great number of this tribe supposed to have died of the plague, on account of fornication and idolatry, made mention of in the preceding chapter; a prince in this tribe having set a bad example, it is probable he was followed in it by many of it, for which great numbers were cut off. Jarchi, from Tanchuma, says, that all the 24,000 that died of the plague was of the tribe of Simeon; and so says the Samaritan Chronicle (o); but that is not likely.
(o) Apud Hottinger. ut supra. (Smegma Oriental, l. 1. c. 8. p. 448.)

The sons of Simeon--It is supposed that this tribe had been pre-eminent in the guilt of Baal-peor and had consequently been greatly reduced in numbers.
Thus God's justice and holiness, as well as His truth and faithfulness, were strikingly displayed: His justice and holiness in the sweeping judgments that reduced the ranks of some tribes; and His truth and faithfulness in the extraordinary increase of others so that the posterity of Israel continued a numerous people.

Jachin - Called also Jarib, 1-Chronicles 4:24. And such names might be either added or changed upon some special occasion not recorded in scripture.