David's mighty men were divided into the three and the thirty. Ittai the son of Ribai of Gibeah of the people of Benjamin is one of the thirty.
(2 Samuel 23:29)
Ittai flees Absalom with King David
Since the hearts of Israel went after Absalom, David told all his servants at Jerusalem, "Arise, and let us flee, or else there will be no escape for us from Absalom. Go quickly, lest he overtake us quickly and bring down ruin on us and strike the city with the edge of the sword." His servants obeyed him, so the king went out and all his household after him. He left 10 concubines to keep the house. And the king went out, and all the people after him. And they halted at the last house.
All his servants passed by him, and then the king told Ittai the Gittite, "Why do you also go with us? Go back and stay with the king, for you are a foreigner and also an exile from your home. You came only yesterday, and shall I today make you wander about with us, since I go I know not where? Go back and take your brothers with you, and may the LORD show steadfast love and faithfulness to you."
He answered, "As the LORD lives, and as my lord the king lives, wherever my lord the kind shall be, whether for death or for life, there also will your servant be." David said, "Go then, pass on."
So Ittai passed on with all his men and the little ones with him, passing the brook Kidron and entering the wilderness.
Abishai leads a third in David's battle against Absalom and Israel
David send out the army, one third under Joab, one third under Abishai the son of Zeruiah, and one third under Ittai the Gittite. David ordered them to deal gently with Absalom, and all the men heard him. (2 Samuel 18:1-5)
The battle was fought in the forest of Ephraim across all the country, and Israel's loss was great against David's servants, 20,000 men. The forest devoured more than the sword.
Joab blew the trumpet and restrained his troops. They took Absalom's body and threw him in a great pit in the forest and piled stones on him.