This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

Amasa's father was Ithra an Israelite.

2 Samuel 17:25 View context

And Absalom made Amasa captain of the host instead of Joab: which Amasa [was] a man's son, whose name [was] Ithra an Israelite, that went in to Abigail the daughter of Nahash, sister to Zeruiah Joab's mother.

Amasa's father was Jether an Ishmaelite.

1 Chronicles 2:17 View context

And Abigail bare Amasa: and the father of Amasa [was] Jether the Ishmeelite.