1 Chronicles 2:17

Overview - 1 Chronicles 2
The sons of Israel.
The posterity of Judah by Tamar.
13 The children of Jesse.
18 The posterity of Caleb the son of Hezron.
21 Hezron's posterity by the daughter of Machir.
25 Jerahmeel's posterity.
34 Sheshan's posterity.
42 Another branch of Caleb's posterity.
50 The posterity of Caleb the son of Hur.
Treasury of Scripture Knowledge

1 Chronicles 2:17  (King James Version)
And Abigail bare Amasa: and the father of Amasa was Jether the Ishmeelite.

2 Samuel 17:25 ; 19:13 20:4-12 1 Kings 2:5 1 Kings 2:32

Jether, [Yether ,] is essentially the same with [Yithr ,] Ithra, the latter only having the addition of an ['Aleph] {aleph;} and it is probable, that he was an Ishmaelite by birth but an Israelite by religion.
2 Samuel 17:25

Ithra an Israelite