//I encounter this objection from time to time. Sin, like obedience is relational. To what? The law. David's sin was that he intended the unlawful slaughter of Uriah. You would agree, I hope, with the idea that David's choice would have been sinful even if Uriah had counter-factually lived. Why? Because David's intention constituted a breach in God's law.
Now, the way in which God relates to the law is different from the way man relates to the law. Example: God can't steal or covet, because He owns everything. But that there is a disanalogy means the burden of proof is on the one who relies on an analogy between the relation between God and the law and the relation between man and the law to show that what applies to the latter applies to the former.
In this case, you suggest that if God sent the Ammonites to kill Uriah, He would have sinned. But God's intentions and David's intentions would necessarily have been different. Uriah was a sinner in God's eyes, as was Isaac when God commanded Abraham to kill him in Genesis 22 or as were the Israelites when God sent the Assyrians to kill them in Isaiah 10. Note that God judged the Assyrians but commended Abraham. Why? Because the immediate intentions of each were that by which each was judged. Hence, Abraham was commended because He obeyed God's precept, whereas the Assyrians were judged because they disobeyed God's precepts.
If any analogy exists, then, it would be between the fact that whether or not one has broken the law is ascertained by checking his - immediate cause's - intentions and how they relate to the law. That's why I've asked repeatedly what law God has broken for having decreed sin or how God has acted contrary to His nature by ultimately causing sin. Your silence suggests you can't think of one, in which case my position stands as do my arguments in its favor.
At most, the above passage shows it is wrong for humans to cause sin. Even disregarding my above points, that itself would be an inductive argument, and inductive arguments are fallacious.
...I have demonstrated God's eternal omniscience necessitates God is the ultimate cause of all things. I have demonstrated that by ultimately causing sin, God's maximally manifests His glory, which, in fact, is what it means to be righteous. I can quote myself again, but I'm getting tired of repeating myself.//
Gordon Clark similarly comments:
"...neither the eighth commandment nor any other applies to God. God cannot steal for the simple reason that he owns everything. Obviously he cannot obey the fifth commandment. God is righteous in the sense that he determines the laws of righteousness; we are righteous in proportion to our obedience to those laws." - The Pastoral Epistles, pg. 119
While Clark's point that God is not obligated to obey the same commandments we are is on the mark, I would add, in conjunction with the above link to the post on John Piper's exegesis of Romans 9, that both God's righteousness and ours can be said to be proportional to how the actions of each reflect God's glory: insofar as God's glory is maximally manifested through God being the ultimate cause of reality, God is righteous, and insofar as man perfectly obeys that which he ought to obey, thus appreciating rather than scorning God's glory, he is righteous.