I would sooner believe the story of Jephthah is fiction, of course, than for a godly man to sacrifice his daughter. But even if the story was based in truth, most believers in God know that the Spirit of God would not rest on a man who would do such a heinous thing. One reason I always despised Agamemnon is for his sacrifice of Iphigenia at Aulis.
Josiah is another story. Most Sunday School children are taught Josiah "did what is "right with the Lord":
Now some scholars aren't so sure.
I know a number of people who don't believe Jesus ever existed. And it's now common for scholars to believe there were a number of different Isaiahs. Yet many evangelicals believe the entire Bible is the complete, inerrant word of God.
It's becoming increasingly difficult to find a common frame, or foundation, of belief upon which to debate. Many of the things we think we know, whether historically, eschatolgically or scienticically, tend to be shattered from time to time. And I've long been suspicious of the story of Sampson. The appearance of the angel, and his disappearance, was strange. Two, Sampson was an idiot in the story, being twice betrayed before his downfall with the third betrayal. Upon seeing he'd been betrayed twice, the story would have made more sense had he strangled the woman. He murdered thirty innocent people to gain their cloaks so he could win a bet. Finally, he didn't fulfill that which he'd been called to do, which was to deliver his people. If this story is true, and I have my doubts, it certainly doesn't reflect well on Israel's God!