Judges 11:39
“And it came to pass at the end of two months, that she returned unto her father, who did with her according to his vow which he had vowed: and she knew no man. And it was a custom in Israel,”
And she said unto her father, Let this thing be done for me: let me alone two months, that I may go up and down upon the mountains, and bewail my virginity, I and my fellows.
And he said, Go. And he sent her away for two months: and she went with her companions, and bewailed her virginity upon the mountains.
And it came to pass at the end of two months, that she returned unto her father, who did with her according to his vow which he had vowed: and she knew no man. And it was a custom in Israel,
That the daughters of Israel went yearly to lament the daughter of Jephthah the Gileadite four days in a year.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Related Verses
“And he said, Go. And he sent her away for two months: and she went with her companions, and bewailed her virginity upon the mountains.”
“And she said unto her father, Let this thing be done for me: let me alone two months, that I may go up and down upon the mountains, and bewail my virginity, I and my fellows.”
“And his concubine played the whore against him, and went away from him unto her father’s house to Beth–lehem–judah, and was there four whole months.”
“And they found among the inhabitants of Jabesh–gilead four hundred young virgins, that had known no man by lying with any male: and they brought them unto the camp to Shiloh, which is in the land of Canaan.”
“And his father in law, the damsel’s father, retained him; and he abode with him three days: so they did eat and drink, and lodged there.”