It appears that God placed the tree of the knowledge of good and evil in the garden to serve as a test of simple obedience.
This does not contradict what we read in the epistle of James: “Let no one say when he is tempted, ‘I am being tempted by God’; for God cannot be tempted with evil, and he himself tempts no one” (Jas. 1:13).
Testing is something quite different from tempting. God tested Adam and Eve, but he did not tempt them. He put the sincerity of their faith and obedience to the test, but he did not allure them to do evil—which is the essence of temptation.
They were tempted by Satan, as well as by their own desires. James tells us, “Each one is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death” (Jas. 1:14-15).
Satan, who is called, “the tempter” (Matt. 4:3; 1 Thes. 3:5), approached Adam and Eve in the garden and appealed to their pride and their desire for autonomy, or independence from God. He said, “When you eat of it your eyes will be opened, and you will be like God, knowing good and evil” (Gen. 3:5). The sense here is, “You will be like God in determining good and evil.” In other words, Satan was suggesting that if they ate from the forbidden tree, they could determine for themselves what was right and wrong. He was tempting them with the prospect of independence from authority of God and the rule of his word.
We are not told what kind of tree the tree of the knowledge of good and evil was. The usual representation is that it was an apple tree. But it may just as well have been a fig, or a date, or even a banana tree! In all likelihood, there was nothing exceptional in the tree itself—nothing in its appearance that would have distinguished it from the other trees. It probably was no different from the other trees of the garden except that God had said, “Don’t eat from it.” There was nothing inherently sinful about eating from the tree, but it became sinful simply because God commanded them not to eat from it.
Now, it would be a mistake to think that this was the only thing that was forbidden to Adam. It would have been unlawful for him to lie, to cheat, to steal, to murder, etc. But in his unfallen state he would have naturally seen the reasonableness for the prohibition against these things. But the command forbidding him to eat from a certain tree—a tree which was in every other respect just like all the other trees of the garden—this was an arbitrary command, and one for which he could see no inherent reason. The command to refrain from eating of it, therefore, was a test of pure obedience. In other words, would Adam obey God implicitly, without being able to understand God’s reasons, or would he follow his own judgment.
In Proverbs, Solomon says, “Trust in the Lord with all your heart, and do not lean on your own understanding” (Prov. 3:5). This is precisely what Adam and Eve failed to do. They failed to trust God implicitly. They were seduced by the suggestion of the serpent that they could be like God in determining good and evil for themselves. They were not content to live within their own creaturely limitations, but instead grasped for a prerogative that did not belong to them.
The trial they faced is not all that different from the one we face, as well. Will we humbly bow before the authority of God, who alone has the right to determine good and evil? Are we willing to live with his definitions—his judgment concerning what is right and wrong? Which is to say, will we confess that he is Lord, and we are not?