Cross reference
2 Samuel 20:4
4 Then the king said to Amasa, Get all the men of Judah together, and in three days be here yourself.
2 Samuel 17:25
25 And Absalom put Amasa at the head of the army in place of Joab. Now Amasa was the son of a man named Ithra the Ishmaelite, who had been the lover of Abigail, the daughter of Jesse, sister of Zeruiah, Joab's mother.
2 Samuel 19:13
13 And say to Amasa, Are you not my bone and my flesh? May God's punishment be on me, if I do not make you chief of the army before me at all times in place of Joab!
1 Chronicles 2:17
17 And Abigail was the mother of Amasa; and the father of Amasa was Jether the Ishmaelite.