There you go, using "allowed" again. In the determinism of your system there is no "allowed". Try being honest.
If everything as claimed in the confession, brought about by God's decree, was there somehow something above God's decree that caused the fall?
God's knowing isn't even the question here, so why appeal to it? That's what an arminian would do.
Did God's Decree Bring About the Fall?
In the past week I have had several people ask me how Adam's original sin come about since he did not have a fallen nature to contend with. Thus it's not that Adam and Eve were originally prevented from obeying God due to a sinful nature, as we are now. Also since God is NOT the author of evil, didn't make Adam sin, nor did HE put the sinful desire within them, so the question is really how (or why) did Adam originally sin? This is really an attempt to understand the relationship between God's sovereignty and freewill in the beginning, prior to the fall.
By confession we believe that God created human beings "with knowledge, righteousness, and true holiness, after His own image; having the law of God written in their hearts, and power to fulfil it; and
yet under a possibility of transgressing, being left to the liberty of their own will, which was subject unto change." (WSF IV.2) This is to say that man was created in such a way where he was not yet sealed in righteousness as he will be in glory, but created with a an inclination toward good. Why evil temptation was able to overcome that inclination, the Scripture does not reveal, so any dogmatic response would be speculative. So while there are indeed mysteries that are not fully revealed to us in Scripture ... on the other hand, there are some things revealed
that we do know and from these we
can draw some conclusions.
Did God's Decree Bring About the Fall?
It is important that we first consider the alternative to God ordaining the fall event to show that it is really quite and untenable and unsustainable position. The truth of God's word is honored not in holding exclusively to one truth to the exclusion of another truth, but in believing the whole counsel of God. The Bible plainly teaches that man is responsible for the sin he commits and it also teaches that God is sovereign. You would be correct theologically to say that God is not the author of evil and that man alone is culpable for the sin he commits. You must also consider, however, that God is sovereign and has thus left nothing up to chance. That word "nothing" is a universal negative. For if chance were to exist then, of course, God would not be sovereign and thus, God would not be God.
God did not coerce Adam to commit sin and fall, but he certainly ordained it. Even an Arminian who thinks that God merely allowed the fall, must admit that before God created the world he already knew what the future would be, and so it was within his Providence for such events to take place, for he could just have easily decided to prevent the fall...but He didn't. But we believe that while God did not make man sin coersively he certainly ordained such events to occur. Consider that if God did not decree the fall then evil is something completely outside His sovereign control ... If evil came into the universe by surprise for God, totally apart from His providence, then there are some things He does not know or things He is powerless over and therefore God would, by definition, lack omniscience and omnipotence. And then how do we know whether He will be able to defeat evil in the future if evil is outside God's control even though the Scripture plainly says that God ordains all events that come to pass (Eph 1:11).
As for how it could be that God decreed the fall. Obviously it is ultimately for His glory. In it He showed to the angels and all creation His manifest wisdom, justice and mercy and all of His perfections. He does not operate people like puppets. Adam freely chose to rebel ... God did not coerce him... and now fallen men freely choose to reject Christ, apart from grace. You ask, how could God ordain evil? Well, let me give you a clear biblical example which shows that he does, so you don't think I am just blowing smoke.
Consider that Christ's crucifixion was a certainty which God planed in eternity and prophesied would come to pass in the Old Testament. But also consider that men would freely choose to crucify the Son of God. See Acts 2:23 which brings the two together -- "this Man, delivered over by the predetermined plan and foreknowledge of God, you nailed to a cross by the hands of godless men and put Him to death." This concurrent series of events taking place simultaneously is called compatibilism, which is how the Scriptures really answer this question.
Part 1...