Matthew Poole and continuators on 2 Samuel 21:8

8 But the king took the two sons of Rispah , the daughter of Aiah, whom she bare unto Saul, Armoni, and Mephibosheth, and the five sons of Michal the daughter of Saul, whom she brought up for Adriel the son of Barzillai the Meholathite .

Saul's Concubine, v. 11. and chap. 3. 7.

Or, of Michal's sister, to wit, Merob: for Michal had no Children, 2 Sam. 6. 23. nor was she Married to this Adriel, but to Phalti or Phaltiel the son of Laish, 1 Sam. 25. 44. and 2 Sam. 3. 15. and Merob her sister was Married to this very Adriel the Meholathite, 1 Sam. 18. 19. And it must be remembred, that the Hebrew Language is very short, and full of Elipses or defects of words, which yet may be easily understood from the sense. Particularly, relative words are oft lacking, and to be supplied, as Goliah is put for Goliah's brother, here v. 19. and Uncle for Uncle's son, Jer. 32. 7, 12. Or, the Sons of Merob are called the sons of Michal, to wit, by adoption; or, the near Kindred and next Heirs of Michal, and brought up by her. For upon that and such like accounts the title of Son is oft given in Scripture, as Gen. 48. 5. Exod. 2. 10. Deut. 25. 5, 6. Ruth. 1. 11, 12. and 4. 17. Quest. But why then are not these called the sons of Merob? Ans. Because they were better known by their Relation to Michal, who was David's Wife, and, it may be alive at this time, and having no Children of her own, took these and bred them up as her own; when Merob was▪ now a more obscure person, and possibly dead many Years before this.

For so this Hebrew Verb, which primarily and properly signifies to bear, is sometimes used, as Gen. 50. 23. Ruth 4. 17. because the Education of Children is a kind of bearing of them, as requiring frequently no less care and pains than the hearing doth; whence it is that Nurses are reputed as Mothers, and sometimes go under that name both in Sacred and Prophane Writers. See Ruth 4. 16, 17. and compare Gen. 16. 2. and 30. 3. Numb. 11. 12. Gal. 4. 19.

Of Abel-meholah in the Tribe of Benjamin. Iudg. 7. 22. So he is here called by way of distinction from Barzillai the Gileadite, chap. 19. 31.

Marginal references: Or, Michal's sister, v. 19.; Heb. bare to Adriel.