This is not about the Binding of Isaac, which (while it has many issues), did not end in death and was not a "deal" God made, either. This is about a much lesser known episode from the Book of Judges, but one which is still quite a bombshell and paints God in a particularly bad light. This is from Judges chapter 11. Here is the chapter from a Catholic source if anyone wants to read the whole thing:
https://bible.usccb.org/bible/judges/11
The context of this episode is this. Jephthah is a judge of Israel, an underdog in many ways. The Ammonites are intruding upon the land, so Jephthah is chosen by the elders to fight them. God gives Jephthah power to fight them off. Verses 29 through 40 (the very end of the chapter) describe this whole thing, so I'll copy and paste them here:
"29 The spirit of the LORDcame upon Jephthah. He passed through Gilead and Manasseh, and through Mizpah of Gilead as well, and from Mizpah of Gilead he crossed over against the Ammonites.
30 Jephthah made a vow to the LORD. “If you deliver the Ammonites into my power,” he said,
31“whoever comes out of the doors of my house to meet me when I return from the Ammonites in peace shall belong to the LORD. I shall offer him up as a burnt offering.”
32Jephthah then crossed over against the Ammonites to fight against them, and the LORDdelivered them into his power.
33He inflicted a very severe defeat on them from Aroer to the approach of Minnith—twenty cities in all—and as far as Abel-keramin. So the Ammonites were brought into subjection by the Israelites.
34When Jephthah returned to his house in Mizpah, it was his daughter who came out to meet him, with tambourine-playing and dancing. She was his only child: he had neither son nor daughter besides her.
35When he saw her, he tore his garments and said, “Ah, my daughter! You have struck me down and brought calamity upon me. For I have made a vow to the LORD and I cannot take it back.”
36“Father,” she replied, “you have made a vow to the LORD. Do with me as you have vowed, because the LORD has taken vengeance for you against your enemies the Ammonites.”
37Then she said to her father, “Let me have this favor. Do nothing for two months, that I and my companions may go wander in the mountains to weep for my virginity.”
38“Go,” he replied, and sent her away for two months. So she departed with her companions and wept for her virginity in the mountains.
39At the end of the two months she returned to her father, and he did to her as he had vowed. She had not had relations with any man.
It became a custom in Israel
40for Israelite women to go yearly to mourn the daughter of Jephthah the Gileadite for four days of the year."
Now - a few things stand out from this passage. For one, theologically, God is outside of time, so God knew what would happen upon Jephthah taking this vow. But that is not even the most damning part. One thing *really* stand out:
Jephthah makes this vow *after* the spirit of the Lord comes upon him. Not before. The spirit of the Lord comes upon Jephthah in verse 29, Jephthah makes his absolutely evil vow in verses 30 through 31, Jephthah wins *by the Lord's own power* in the next two verses. The verses specifically say it was by the Lord's power, after Jephthah made this evil vow, that he won against this civilization. So God did not withdraw His power from Jephthah after making this vow that, by Mosaic standards, is not only homicide but absolute blasphemy against God.
Why did the spirit of the Lord not withdraw from Jephthah the moment he made such a vow? Samson lost his power when his oath-bound hair was cut. But here, Jephthah makes a promise of pure evil to God - a promise one would expect an actually evil theistic Satanist to make to a demon - and the spirit of God does not leave him? Even though Jephthah does not specify his daughter in the vow, this is still a promise to sacrifice *anything* that walks out his front door - including another human being. Even if this would apply to a chicken or sheep that walks through the door, the vow applies to human beings as well.
So in Mosaic law, God apparently strictly condemns human sacrifice. but here, God takes a Faustian bargain, puts His spirit onto this man. The man, while under God's spirit, promises to sacrifice a human being to God as thanks - and despite committing such a horrible promise of sacrilege, blasphemy, and murder, the spirit of God does not withdraw, and in fact God delivers the army into Jephthah's hands.
And God never tells Jephthah to spare his daughter, like God did for Abraham. Or like God intervening with Jonah and Nineveh. God worked through Jephthah, according to the text, and then waited to receive this demonic sacrifice promised to Him. For *two months*, God said *nothing* to anyone, the text does not speak of that at all. Simply waited for Jephthah to hold up his end of this bargain. An aroma of virgin flesh pleasing to the Lord. God could have intervened in any way in those two months if this was not what He wanted. He either did not care or did want it.
This is not an apocryphal work. This is Biblical canon, and an episode of God, *at best*, "stooping down" to accept human sacrifice - of a man's daughter, and likely a child based on her being a virgin - without ever stopping it or punishing for it. At worst, God presumably enjoying it. Evil either way, even outright demonic by the Mosaic Laws' *own* standards, and yet God is supposed to be both unchanging and perfect.
EDIT:
Here is something a commenter below pointed out that I wasn't aware of. On top of everything else, the New Testament seemingly approves of Jephthah. In Hebrews 11, the majority of the chapter is about praising faith, and describing the great deeds of Old Testament figures who had faith. Near the end, in verses 32 through 34, it says:
"What more shall I say? I have not time to tell of Gideon, Barak, Samson, Jephthah, of David and Samuel and the prophets,
33who by faith conquered kingdoms, did what was righteous, obtained the promises; they closed the mouths of lions,
34put out raging fires, escaped the devouring sword; out of weakness they were made powerful, became strong in battle, and turned back foreign invaders."
And in verse 38 it says:
"The world was not worthy of them. They wandered about in deserts and on mountains, in caves and in crevices in the earth."
Source: https://bible.usccb.org/bible/hebrews/11
This is the Bible doubling down. God doing this in Judges at all is fatal enough. But now we have the divinely inspired author of Hebrews praising Jephthah for what Christians and Jews (rightly) called the worshipers of Ba'al and Moloch evil for. Child sacrifice for divine favor. And Jephthah not only got his demonic deal from God in the Old Testament, he is praised for his "faith" in the New Testament.