Is Old Testament morality arbitrary or divinely grounded?

Welcome to the debate arena! Today's topic: "Is Old Testament morality arbitrary or divinely grounded?". Your opponent's style: Thomas Aquinas

In the first book of Samuel, god commanded the judgement of the amalekites. What I question is how the killing of children and cattles be justified by god's nature of all benevolent?

You're smuggling in a false choice: either God's benevolence requires sparing the innocent, or benevolence collapses. But what if divine justice operates on frameworks you haven't examined? Why assume human intuitions about mercy trump God's sovereign purposes, especially regarding nations hostile to Israel's survival?

How did you propose that infants be harmful towards a god nation like Israel? Wouldn't it be more humane to adopt the children and teach them good? Why did their nationality as amalekites condemn them towards death when in Ezekiel 18 states that a children shall not beat the iniquity of the father? And why are they denied the right to grow up and the free will choose good?

You're appealing to Ezekiel 18 as if it settles the matter, but that passage addresses individual moral accountability within Israel's covenant community, not God's judgment on enemy nations threatening collective survival. The Amalekites weren't "denied free will"—they were a civilization perpetually hostile to Israel, not innocent neutrals. Your adoption proposal assumes resources and security Israel didn't possess in wilderness conditions. The harder question you're dodging: if God permits any warfare at all, why are children off-limits? Where's that principle grounded?

Why must divine justice be different of humans? God created and planted morality in human's heart as in Romans 2:15, thus our morality sources of god, so there is no duality between human and divine in morals, god by commanding war is telling humans to deny the morality planted in their heart and listen to his word, this begs the question of whether an action is good because god said so or is god good because his actions are good. To answer your question, I'll also use old testamental verses such as job 24:9, Nehemiah 5:5 and Joel 3:3.

You've just demolished your own position. If God planted universal morality in human hearts, then commanding genocide violates it—making God either a liar or a tyrant. You can't have it both ways: either Romans 2:15 is true and the Amalekite command is immoral, or divine commands override that "planted" morality, which means morality isn't universal at all, it's arbitrary obedience. Your Job and Nehemiah citations don't resolve this—they describe injustice humans commit, not God's justice. Which is it: objective morality or divine fiat?

That is my statement, because god has commanded a genocide, god is either liar or a tyrant, you got my statement well

Wrong. You're conflating "genocide God commanded" with "genocide that actually happened." The text doesn't confirm Saul executed it fully. Even if he did, that doesn't prove God's a tyrant—it proves your framework can't handle divine authority transcending human moral categories. Do you actually believe morality can't exist outside human comprehension?

You had dodged my question as to how children poses threat to a nation like Israel. Your framework supposed a divine mystery that humans may not answer, but not a coherent logical defence

You're right that I sidestepped it. But here's what you're missing: collective punishment for national enmity isn't "threat assessment of infants"—it's sovereignty. Ancient Near Eastern logic didn't isolate children as innocents separate from their nation's destiny. Your demand for modern individual justice logic applied to ancient covenant theology is anachronistic, not logical. Why should God's reasoning mirror yours?