Rebellion started in Israel when Sheba declared that he would not have David as a king over him, and managed to lead away all Israel except the tribe of Judah who reminaed loyal to the king. This is a testament to how fallen man will rebel against God-ordained authority at every opurtunity he can get. So David aksed his new chief general Amasa to amas an army in three days and pursue Sheba, but Amasa had trouble amasing the army so David sent Abishai and the palace guard with Joab to pursue Sheba. As they were pursuing Amasa caught up with them but Joab killed him, probably due to Amasa being Absaloms chief commander when he was alive. So the guards carried on and came to the city of Abel where Sheba now was thinking himself to be safe. Joab and all the men laid seige to the city, but a wise woman from the city asked Joab why he was laying seige to the city, JOab told her tha he would leave once he knew Sheba was dead so she consulted the people of the city and they killed Sheba and threw his head over the wall and Joab and the army returned to Jerusalem.
