Joab killed his first cousin Amasa; Solomon killed his first cousin Joab

[TonyChanYT]

1 Chronicles 2:

13 Jesse was the father of Eliab his firstborn; the second son was Abinadab, the third Shimea, 14the fourth Nethanel, the fifth Raddai, 15the sixth Ozem and the seventh David. 16 Their sisters were Zeruiah and Abigail.

Zeruiah was a sister of David.

Zeruiah’s three sons were Abishai, Joab and Asahel.

Joab was a nephew of David.

17 Abigail was the mother of Amasa, whose father was Jether the Ishmaelite.

Joab and Amasa were first cousins.

David promoted Amasa and demoted Joab in 2 Samuel 19:

13 And say to Amasa, ‘Are you not my own flesh and blood? May God deal with me, be it ever so severely, if you are not the commander of my army for life in place of Joab.

Later, Joab killed Amasa in 2 Samuel 20:

9 And Joab said to Amasa, “Is it well with you, my brother?” And Joab took Amasa by the beard with his right hand to kiss him. 10But Amasa did not observe the sword that was in Joab’s hand. So Joab struck him with it in the stomach and spilled his entrails to the ground without striking a second blow, and he died.

Solomon and Joab were first cousins. After David's death, Solomon killed Joab (1 Kings 2:34) according to David's wishes.

Joab also killed his first cousin Absalom (2 Samuel 18:15).