We have to view the whole counsel of God. Not just individual sections of scripture or attributes of God.
God has decreed everything that occurs or he would not be sovereign, in a way that he is not responsible for the "bad" outcomes, or he would not be Holy. It is not a contradiction for an infinite being. There are many such primary paradoxes when you view God's attributes, how does he remain both loving and just, how does he maintain Man's free will, and his own sovereignty? These are questions we cannot fully answer.
Simplistically, God created man, gave him a free will, and decreed the fall (in a way that he is not responsible for it) in order for him to be given an opportunity to show mercy, but in order to maintain his justice and holiness, equal payment had to be exacted (not identical payment). He sent his Son (both fully human, and fully God, another interesting paradox) and Jesus Christ lived a sinless life, and offered himself as the spotless lamb to fulfill the debt we as sin cursed humans could not pay. He also decreed those to be elect of whom he had intimate knowledge of before the creation, in such a way that he is not responsible for their 'choice' to reject Christ. They will get what all mankind deserves, and is destined for without Christ. There are elements of God's sovereign will and man's ability to choose in the body of scripture dedicated to Salvation, you cannot avoid either one.
It really comes down to perspective. From a human perspective, our only chance is to accept the free Gift of Eternal life. The only way IMHO that we can do this scripturally is through the impartation of spiritual life to us by the spirit as a part of our salvation. But to us, it is a choice we must make. From God's perspective, he is in control, and "knows them that are his" and he must, in order to remain God!
Ok, so simplistically was not the word for that, but it is a much different scenario talking about salvation from a evangelistic perspective, to a theological one.
I can't wrap my finite brain around that concept either, but the facts are there, as Dr. Bob said above, both the sovereignty of God in Salvation, and the Responsibility of man to live with the consences of his choices is taught in scripture.