“King David sent this message to the priest Zadok and Abiathar. ‘Say to the elders of Judah. Why should you be the last to bring the king back to his house? The talk of all Israel has come to the king. You are my kinsmen. You are my bone and my flesh. Why then should you be the last to bring back the king?’ Say to Amasa. ‘Are you not my bone and my flesh? So may God do to me, and more, if you are not the commander of my army from now on, in place of Joab.’ Amasa swayed the hearts all the people of Judah as one man. They sent word to the king. ‘Return, both you and all your servants. So the king came back to the Jordan. Judah came to Gilgal to meet the king and to bring him over the Jordan.”
On the other hand, King David was making plans to return himself. This might work out. First, David wanted to get the people of Judah on his side via the priests Zadok and Abiathar. The people of Israel wanted him to come back from the other side of the Jordan. He wanted the people of Judah to know that he was from Judah. It was then that he promised to make Amasa the head of army, replacing Joab, who also was a cousin of both Joab and Absalom. Amasa persuaded the others to accept David. So the first move was to get him to the west bank of the Jordan. The people of Judah went out to meet David him at Gilgal.