Humans are obscure creatures unlike any other. We are made very much in the image of God, but we are so far from the magnificence of God. We think we are nearly so but are sadly mistaken.
One of our obscurities is that we have the same faculty that God has but ours is used so much differently. The will is the faculty of human mind which, when given a decision, deliberately selects the one which is the strongest desired. Reason and understanding are other activities of the mind as well, and the three are sort of a psychological trinity.
God has His will also. That's why mankind was endowed with one - in God's image! In the beginning, God's will was Adam's will, and mankind was in innocence. Adam was in harmony with God. Adam was willing to tend God's Garden out of love, respect, and appreciation. Adam was truly free because he had never been confronted with tough decisions. Alas, God must test him! Satan's purpose is "tough tester" but with God it's not a scale but pass or fail! Man's will is the instrument which is used to test.
For will to work, the mind must process the input. In theology, there are two kinds of inputs: the will of God and the will of Satan. Divine influence is the former, and temptation is the latter. The will of God is good, and the will of Satan is evil. Good brings happiness and forgoes stress. Evil brings illicit pleasure and brings on stress - unless the person is acclimated to sin, and that is called reprobation.
Mankind was given a will so that we were more than automatons. God could have made us in the image of a robot. He could have made us to obey every command without question. Why did he not do so? Our will is the method of showing love or disdain for God. Robots cannot love - they can only obey. This difference is part of the mystery of God. He never ever was satisfied with obedience; He just wanted his creation's love.
Obedience is done out of obligation. People obey out of fear of punishment. Love is voluntary. Obedience and love both result from exercising the will. God doesn't want us to fear Him in the sense of being imprisoned by His rules. His desire is that we revere Him for his goodness. We all deserve punishment because of our disobedience, but God's grace is that He is merciful, and loves even the disobedient.
God does have one expectation: Because we are His children it is our love that is expected! Mankind exists because God wanted companionship, and to receive rebellion is pathetic on mankind's part. We are the monsters who turned on our creator. Rather than being appreciative for our very existence, we are frustrated, and even resentful, that there are rules of divine civility to follow!
Rules are made as tests of love. God's only command in the beginning was to never eat of the forbidden tree. In essence, God gave mankind only one decision to make: show me love by obedience to this one command. Man could not oven keep one command! Later on when he was given ten, breaking the one was as breaking them all because all God's commands are metrics of love.
Each time there is temptation, the person must make a decision. Man understands the options, and reasons with himself. Shall I or shall I not? The will is when the decision is made. In theology, the output to temptation is to either sin or not to sin. Sin is always willingly, but it is not always actively. Willful sins are done on purpose with aforethought. Sins of omission are done due to willful negligence. God calls us to love him, but because we neglect Him, we are sinful. There are even accidental sin - those we do because we're clumsy with God's rules. (e.g.; because of negligence, not carrying the ark of the covenant as it was supposed to be carried).
As such, God expects us to use our will. Since there are no constraints put on our decisions, human will is free-will. God respects our humanity so much that he allows us to make our own choices. Our eternal destiny is the utmost choice that we shall ever make.
God created time for this very purpose! Everyone has an entire lifetime to choose mortality or immortality. Actually, life never ends for anyone - the material dies but the spiritual lives on. The atmosphere of eternal death is isolation, hate, decay, and pain, while the atmosphere of eternal life is communion, love, preservation, and comfort! Our destinies are our choices. God gave us free will to choose either foolishly or wisely. Only a fool would choose suffering, but that's what most people choose!
Those who are strong-willed resist making a decision. That's why God by grace allows a lifetime! The notion is that the decision is put off, but actually the procrastination in itself is a decision. Most assume that time will always be there to decide later. God knows the hearts, thus the will, of everyone. Because of foreknowledge he knows whether our hearts are tender enough to be circumcised. With some, God will cut the life short because He knows that they will never be willing to submit.
Others use their free-will to choose eternal death because they just don't believe God. Although, as children of God, mankind was created in His image, when men freely choose to do the will of Satan, they became children of the devil. Our divine parent is who we belong to, and those who choose the will of Satan, choose him, and have no rights because they are not legitimate heirs of God. Satan uses deception to confuse the will of every individual. Discernment is when people use their will with eyes wide open - in truth. Satan speaks some truth but adds to it lies which lead to destruction. He knows how easy it is to confuse the mind, allowing mankind to do unreasonable things because they fail to understand.
God did this in the Garden. I don't know about Eve, but Adam made a conscious choice. (Eve may have just misunderstood Adam's instruction because the rule was given to Adam). Adam looked at the tree with its fruit, understood God's command, reasoned about the choice between life and death, and willingly ate thereof. Hence, Adam was credited with the first sin.
Adam stood by and watched Eve pleasure in what she ate. Since Eve didn't die as God said she would, Adam reasoned (rationalized) and ate as well. In effect, Adam considered God a liar. His mind was confused by entering into the place of temptation. God meant eternal death, but Adam only considered physical death, not realizing that God's intent was for them both to live forever. At that instant, Adam and Eve went from immortal to mortal, and ever since, mankind has tried to regain eternal life. The problem lies in the method. Some trust science and humanity while others trust God.
Because men are unwilling to trust God for eternal life, their trust is in mankind, especially themselves. Some do their own will without regard to God's will, caring not that they shall go to hell, or letting Satan convince them: thou shall not surely die. Those who use their will to do their own thing, trust that the few good things will save them in the end because God is good. If they do some "good", then a good God will save them, although they are unwilling to obey or even to love.
Scripture calls on those who are born-again to make themselves a living sacrifice. The new birth is when people are willing to trust and accept God. That is called faith. God gives faith as a gift but people must accept it. That's a decision which must be made. The person must be willing to be born-again. The old person dies, and the sinner willingly puts that old self on the cross with Jesus. They quit hating, and begin loving. They quit rebelling and begin to obey - not because they must but because the old rebellious self was supposed to have died!
Most believe, many accept Jesus, but few die to the flesh because they are unwilling to make that sacrifice. The hope of salvation is more than belief - it is trusting. Belief is knowing that God can save, and that we can't. Therefore, most accept Jesus, but few are willing to put their old self away. Like Lot's wife, they look back at the pleasure and die, because of their unwillingness to avoid temptation. That's why Paul admitted, "The spirit is willing but the flesh is weak." We want to obey but our human nature isn't willing! There is power in the Word, and absorption in it can strengthen the flesh. It can become more willing when Christians truly submit to God.
Submission to God is defeating Satan. Two masters are traded for one, and ironically, God, although the Master, allows Christians liberty. We can choose to sin if we desire, but the circumcised heart is a willing heart!