Now Jephthah the Gileadite was a mighty man of valor, and he was the son of a prostitute: and Gilead became the father of Jephthah.
The justice and lovingkindness of God appear in the contrast between Abimelech  (Judges 10) and Jephthah here.  Even the son of a harlot became the charismatic leader of Israel in a time of danger.  The Spirit of God came upon him.