Here is a very old question:
"Is it wrong because God says it or does God say it because it's wrong?"
I affirm that the divine Law was derived from the benevolent nature of God and His infinite intelligence!
God's own well-being has intrinsic value and we were made in His image, so our own well-being has intrinsic value, unless we forfeit the right of well-being by sinning against anothers well-being.
The divine law is in no sense grounded upon the arbitrary will of God, but is derived from God's benevolent nature and infinite intelligence to secure the highest well-being of all.
God is against lying, because lying is destructive to the highest well-being of all.
God is against stealing, because stealing is destructive to the highest well-being of all.
God is against homosexuality, because homosexuality is destructive to the highest well-being of all.
God commands that we love Him supremely and our neighbor equally, because love promotes the highest well-being of all.
God is no way arbitrary gives commands, but has a loving and wise reason for all that He commands. He is interested in the well-being of all, and is wise enough to see what is good and what is bad for us.
To say that God's arbitrary will is the grounds of moral obligation is to say that God has no good reason for what He commands, and could have just as easily established the law of hate as moral law. But God does have very loving and very wise reasons for His commands, His divine Law is derived from His divine nature and infinite intelligence, which seeks to secure the highest well-being of all, because of the intrinsic value of well-being.
Is it wrong because God says it or does God say it because it's wrong? I affirm that God says it because it is wrong. The revealed law of God was in no way originated, but rather declared. The will of God does not originate moral law, but it is rather declaratory. Moral Law has existed as long as God has existed, as long as God's nature and intelligence has existed.
This is not God establishing morality by some outside standard, rather it is an internal standard, His own nature and intelligence. God declares and enforces moral law, but does not originate it arbitrarily. God expects us to live by the same law that He Himself lives by, the law of benevolence.
The intrinsic value of well-being has existed as long as God has existed, and it is that intrinsic value which is the true ground for morality, which God seeks because of His nature, and God knows how to secure because of His intelligence.
I would highly recommend Charles G. Finneys lectures on The Foundation of Moral Obligation. Finney lectured on theology for over 40 years at Oberlin College.
You can find his lectures here: http://www.gospeltruth.net/1851Sys_Theo/index1851st.htm
