No Christian can in the very least deny that God allowed Hitler to become what he became.
No Christian who believes omniscience entails God knowing every detail of the future can deny God knew every detail about Hitler before he would ever be born including all of his family genealogy.
Where Christians may differ on would be in whether God was directly or indirectly involved (or both at different points and times) in the experiences that conditioned the man to be what he became.
One thing seems clear to me, God did not restrain Hitler to the extent He restrains the sins of other men more commonly. For reasons mostly unknown, God allowed such devastating evil to abound in that region of the world for a time at a particular time in history. In some sense, we have to accept that it was the will of God. At any time God could have prevented Hitler from becoming what he became. Yes God allowed it all, while being powerful enough to prevent any of it from occurring. Whatever He is powerful enough to prevent, but does not, is His will in the sense of allowing it to occur, but not His will in the sense that any should transgress His Holy law. To get a better idea of what is going on in the one will of God, here is a quote from an article that might be helpful:
"The Bible speaks of the "will of God" in several different ways, and it is important to understand the differences.
(1) The
decreed will of God. This is God's eternal, foreordained plan and purpose, which will not change and cannot be thwarted. It includes our salvation (Ephesians 1:3-6, etc.) and His choice and calling of Israel (Romans 11:1-2, 29). God's covenant purposes and promises are a part of His decree, and He will not and cannot "change His mind" about these things (see Exodus 32:13). (If you look at verse 14 of Exodus 32, you might say, "But, look, God did change His mind!" No He didn't. The text says that God "changed His mind" about destroying Israel, and making a new nation of Moses. Moses' whole argument is that God made a covenant, and He cannot change His mind, because He is God. God's "changing His mind about destroying Israel" is really His not changing His mind, about saving this nation and bringing them into the land, in fulfillment of His covenant with Abraham.)
(2) There is what we might call the "
perceptive will" of God. This is God's will, expressed in the form of principles or precepts given to men. The command not to murder lets us know it is God's will for us not to murder others. The command not to steal makes it clear that God's will for us is not to steal. If I say, "I have discerned that it is God's will for me to rob banks, and to kill those who get in my way", we can confidently say that is not God's will His written Word is the expression of His will. In this sense, many people are seeking God's will when it is already obvious. You don't have to pray about living with your boyfriend; God has spoken (Hebrews 13:4; 1 Corinthians 6:9-20).
(3) There is also God's
preferential (desiderative) will. This has to do with what gives God pleasure, and what does not. We know that God loves to show mercy, and yet He will execute judgment (Exodus 34:6-7). It is on this basis that Moses appeals to God to forgive Israel, not only here, but many times (see Numbers 14:17-19). Not only Moses, but others prayed that God would show mercy (Nehemiah 9; Daniel 9). God takes pleasure in the salvation of sinners; He does not take pleasure in pouring out His eternal wrath on sinners (Matthew 18:14; 1 Timothy 2:3-4; 2 Peter 3:9; Ezekiel 18:32; 33:11). When we come to things which are not clearly prescribed as sin, or things which are commanded, our desire should be to do that which pleases God (Romans 12:1; Colossians 1:10; 2 Corinthians 5:9; Ephesians 5:10).
(4) There is what we might call God's "
permissive will." This is what God allows, even though it is sin. God allowed Joseph's brothers to betray him, and to deceive their father, so that He might bring the Israelites (few in number) to Egypt, where God would spare them, and they would greatly multiply (Genesis 50:20). God allows man to reject the gospel, to willfully disobey His laws, to persecute the righteous, and so on. But in all of this, God is still in control, and His purposes are being accomplished. His "decretive will" often allows or permits (His permissive will) men to violate His preferential will (what gives Him pleasure) and His prescriptive will (His Word). God's permissive will is never outside His decretive will. God "permits" those things which will lead to the accomplishment of His decretive will.
(5) There is also God's "
directive will." This is God's personal guidance in our lives. It does not violate any of the "wills" above. There are times when God wants us at a certain place, doing a certain thing. The Bible most often will not provide us with this direct and personal revelation of His will. I can think of God's directive will being revealed in the "Macedonian call" (Acts 16:6-10). I can see it in the direct guidance of Philip (Acts 8:26) and of Peter and Ananias (Acts 10:1-23). God does guide us personally and directly, but it seems that this is not as common as some would like. This seems to be required at certain points of our life, when specific guidance is needed (see also 1 Timothy 4:14?).
(6) There may be yet another category, that I might call the
"discerned" will of God. This is my perception of God's will for my life, which comes through wisdom. You may wish to look at the lesson I've done on this in Proverbs."
SOURCE
These distinctions would not amount to the many wills of God, rather different aspects of one and the same will. These are the sorts of issues we run into when trying to put into human language and terms the divine realities of God.
But then again, we have to deal with passages such as
Ephesians 1:11 "Him who works all things according to the counsel of His will." While the first part of the passage is speaking about believers, the elect in Christ, the second part of the verse quoted here might be debatable as a proof text, it could be argued "all things" for the elect according to His will.
However we still have to deal with the fact God is sovereign, all knowing, and all powerful, and isn't so concerned about one person's "free will" that He would not violate it to save millions of lives, one might even argue that would be the most loving thing to do, so a "free will" argument cannot get a free pass here.
