JOAB, 1. Son of David's sister
=>Commander of David's army
2 Samuel 8:16
16. And JOAB the son of Zeruiah was over the host; and Jehoshaphat the son of Ahilud was recorder;
2 Samuel 20:23
23. Now JOAB was over all the host of Israel: and Benaiah the son of Jehoiada was over the Cherethites and over the Pelethites:
1 Chronicles 11:6
6. And David said, Whosoever smiteth the Jebusites first shall be chief and captain. So JOAB the son of Zeruiah went first up, and was chief.
1 Chronicles 18:15
15. And JOAB the son of Zeruiah was over the host; and Jehoshaphat the son of Ahilud, recorder.
1 Chronicles 27:34
34. And after Ahithophel was Jehoiada the son of Benaiah, and Abiathar: and the general of the king's army was JOAB.
Commander of David's army - JOAB-1. Son of David's sister JOAB in Naves Topical Bible (Bible History Online)