The sons of Abraham: Isaac and Ishmael.
Israel was the chosen nation, elect in type; no other people in their national capacity held the covenant privilege the Jews held. The Lord knows His own by name, and many good souls outside Abraham's seed surely found favor with Him, but this genealogy traces the one nation incorporated into His peculiar bond. The Ishmaelites get scant notice because they were cast out as children of the bondwoman, and their rejection foreshadowed the unbelieving Jews rejected after.
AI summary
Commenting on 1 Chronicles 1:28-54
Abraham's sons here are Ishmael and Isaac, along with the sons of Keturah. The genealogy runs exactly as Genesis records it. Note that Timna in verse 36 is not a man but Eliphaz's concubine and Amalek's mother, as the Arabic version and Alexandrian Septuagint correctly read it.
AI summary
1Ch 1:28 The sons of Abraham. - In 1Ch 1:28 only Isaac and Ishmael are so called; Isaac first, as the son of the promise. Then, in 1Ch 1:29-31, follow the posterity of Ishmael, with the remark that Ishmael was the first-born; in 1Ch 1:32 and 1Ch 1:33, the sons of Keturah; and finally in 1Ch 1:34, the two sons of Isaac.