‘And so it was that at the end of two months she returned to her father, who did with her according to his vow which he had vowed. And she had not known man.'
Obedient to her calling and to her father's vow, she returned, and he took her to the central sanctuary and there she served Yahweh at the door of the Tabernacle, possibly even as a prophetess. The only thing that bound her was her father's vow and her gratitude to Yahweh for the victory he had given to her father. She was a lifelong Nazirite (Numbers 6:2). The same would later be true of Samuel. It was such people who kept faith alive in the darkest days.
“Did with her according to his vow which he had vowed.” This personal action seems more to support the view that he took her to the Tabernacle and committed her to Yahweh and the life of a Nazirite than that she was offered as a burnt offering. Had it been such a positive and outstanding act it would surely have been described and such an act could not have been done personally. All Gilead would have been involved in something so dramatic following the defeat of Ammon, and all Israel would have been appalled. But we have no hint of disparagement from the writer.
Those who support the idea that he actually did offer his daughter as a burnt offering claim that the silence on the matter demonstrates the writer's disapproval. But it is difficult to see how such an act could have been portrayed as a personal action.
‘And it was an ordinance in Israel that the daughters of Israel went yearly to rehearse with (or ‘celebrate in song') the daughter of Jephthah the Gileadite four days in a year.'
Jephthah's daughter became an inspiration to the women of Israel. Every year they would gather and ‘rehearse' with her the righteous acts of Yahweh (compare Judges 5:11 - same word) and celebrate her life and devotion in song. And it seems very probable that she became a source of guidance and comfort to them in their lives, and an inspiration to Israel. For all who saw her would know of her obedience and dedication to Yahweh and would remember the great victory that Yahweh had given them through her father.
“Four days in a year.” This may have been, for example, a day at each of the three covenant feasts and on the day of atonement. That seems more likely than a four day feast. Those who see her as sacrificed literally see this as referring to a feast of lamentation and many see it as Israel's equivalent to the feast of weeping for Tammuz celebrated elsewhere.