2 Samuel 17:25

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.

Ver. 25. Ithra an Israelite,] sc, For his faith and religion, as by nature he was an Ishmaelite. 1Ch 7:17

That went in to Abigail,] i.e., Married her; went in to the wedding chamber to her, as Judges 15:1 .

The daughter of Nahash.] Otherwise called Ishai, the father of David; wherefore many Greek copies for Naas have Jesse, and both Josephus and Jerome affirm him to be the same. Kimchi thinketh he was called Nahash, or Serpent, per antiphrasin, as being void of venom or bitterness.