Their sisters were Zeruiah and Abigail. The three sons of Zeruiah were Abishai, Joab, and Asahel.
Amasa Quotes
Amasa or Amessai is a person mentioned in the Hebrew Bible. His mother was Abigail (2 Samuel 17:25), a sister of King David (1 Chronicles 2:16,17).
Attribution
Quotes and notes from Wikiquote: Amasa (page history), available under CC BY-SA 4.0.