I have been reading The Marrow of Modern Divinity for my own personal growth and was helped by this and pray you are.
Legalist: But why then did not the Lord create [Adam] immutable [i.e., unable to sin]? Or, why did he not so over-rule him in that action, that he might not have eaten the forbidden fruit?
Evangelist: Because [God] would be obeyed out of judgment and free choice, and not by fatal necessity and absolute determinism. . . Why did [God] not uphold [Adam] with strength of steadfast continuance; that rests hidden in God’s secret council (p.55-56)
Notice the answer comes in two parts:
(1) God did not create man as mere automatons. We are not like animals who must obey without a will or emotion or desire. Christianity is not determinism. It affirms the free will of man and the rule of God–not in spite of, but through the agency of those decisions.
(2) This might be the harder answer for us to accept, but it resides in God’s perfect and holy and infinite autonomy. An autonomy that supersedes but does not counter-act our autonomy.