I'll just focus on Jephthah's vow, here:
I think the story of Jephthah's vow is very clear cut, and it is extremely obvious that Jephthah sacrificed his daughter to Yahweh:
Jephthah made a vow to the Lord, and said, “If you will give the Ammonites into my hand, then whoever comes out of the doors of my house to meet me, when I return victorious from the Ammonites, shall be the Lord’s, to be offered up by me as a burnt offering."
Who comes out of the doors of Jephthah's house to meet him, when he returns victorious from the Ammonites?
Then Jephthah came to his home at Mizpah; and there was his daughter coming out to meet him with timbrels and with dancing. She was his only child; he had no son or daughter except her. When he saw her, he tore his clothes, and said, “Alas, my daughter! You have brought me very low; you have become the cause of great trouble to me. For I have opened my mouth to the Lord, and I cannot take back my vow.”
Remember: Jephthah vowed to make a
burnt offering of whoever comes out of the doors of his house to meet him. That was the vow.
How does his daughter respond?
My father, if you have opened your mouth to the Lord, do to me according to what has gone out of your mouth, now that the Lord has given you vengeance against your enemies, the Ammonites.
What does Jephthah do?
At the end of two months, she returned to her father, who did with her according to the vow he had made.
Don't forget: Jephthah vowed to make a burnt offering of whoever comes out of the doors of his house to meet him. That's what the Bible says. That was the vow.
In the end, "there arose an Israelite custom that for four days every year the daughters of Israel would go out to
lament the daughter of Jephthah the Gileadite." They lament her, because her father "did with her according to the vow he had made," i.e. burnt offering.
Now, you say:
There is no indication in the text that God approved of the vow that Jephthah made, nor endorsed it in any way. We should not assume that the Bible approves of Jephthah's vow or behavior.
If you flip back to Judges 10, you'll find this passage:
The Israelites again did what was evil in the sight of the Lord, worshiping the Baals and the Astartes, the gods of Aram, the gods of Sidon, the gods of Moab, the gods of the Ammonites, and the gods of the Philistines. Thus they abandoned the Lord, and did not worship him.
Judges is full of moral commentary. It's full of passages like this one, where individuals/groups are described as doing what is "evil in the sight of the Lord." It's not as if the author(s) of Judges impartially describes 'things that happened' without commenting on whether or not those things were good or evil according to God.
So, the fact that the author(s) of Judges never bothered to write that Jephthah's sacrifice of his daughter was "evil in the sight of the Lord" tells us something important. If these author(s) had believed that what Jephthah did was so horrendously "evil in the sight of the Lord," we have every reason to think that
they would have said so explicitly.
The moral of the story of Jephthah's vow is pretty obvious: If, like Jephthah, you make a vow to sacrifice whoever comes out of your house to greet you when you come home from war,
you must keep your vow to Yahweh, even if it means you have to make a burnt offering of your only daughter.
In summary:
- Judges 11 clearly states that Jephthah made a burnt offering of his only daughter.
- The author(s) of Judges are not shy to point out when they believe a person has done something evil.
- In the Bible, the story of Jephthah's vow is depicted as a tragedy, but Jephthah is never depicted as 'evil' for keeping his vow to Yahweh.
- The moral of the story is that "breaking a vow to Yahweh" is a greater offense than "sacrificing your child to Yahweh."