Here is the pertinent portion of the previous link to which I referred.
FREE WILL is a hallmark of orthodoxy. It is believed not only that it is true, but that it is essential, upright and noble. Many even claim that it is the chief capacity distinguishing man from beast. Consequently, its proponents often become filled with “righteous indignation” at the least suggestion of its untenability.
They seek to discover this idea in the Scriptures, and are confident that they have done so in many places. But their sedulous efforts are in vain, for, it is nowhere expressed, frequently disproved, and only falsely inferred.
What those who advocate “free will” actually mean to stand for by means of this expression is the notion that men have the power of
contrary choice: Even though, in fact, we chose as we did, we
could have chosen otherwise. That is, we could have done so
at that time.
It is not contended (nor is it disputed) that, hypothetically and by itself,
we might have chosen otherwise. That is not the idea at all. Instead, it is claimed that, notwithstanding the fact that we
did choose as we chose, we nonetheless
could have chosen otherwise.
This, and this alone, is the question to be resolved.
Advocates of this position, which should be called, “the power of contrary choice,” prefer to perpetuate it instead under the innocuous and advantageously ambiguous title “free will.” At once, this gives it the advantage of a respectable-sounding name, and makes those few who are constrained to reject the actual doctrine appear as strange extremists, inasmuch as they reject such a well-accepted, desirable and seemingly reasonable concept.
The advocate of free will actually stands for the position which asserts that man’s choices are uncaused—absolutely devoid of all necessity. And yet he does not realize, or at least he refuses to admit the fact, that the denial of causality will not bring him any closer to what he wants than its advocacy.
Essentially this matter is a simple one: It is impossible to prevent anything that is the product of a cause from coming into existence;
and, it is also impossible to prevent anything that is
not the product of a cause from coming into existence. If a truly uncaused event were ever to occur (were such a thing even possible), being the product of nothing, uninfluenced and uninfluenceable, it would simply “show up,” appearing “out of nowhere.” While it would not be brought in, neither could it be kept out.
Whether “determinism” (i.e., causality), divine or otherwise, is true or false, we cannot possibly be free either way—that is, in a freewill or contrary-choice sense. If we are
caused to choose as we do, we cannot help choosing as we do. And, if we are
not caused to choose as we do, we still cannot help choosing as we do.
“Surely we cannot be free agents, in the ordinary, strong, true-responsibility-entailing sense, if determinism is true and we and our actions are ultimately wholly determined by causes which existed anterior to our own personal existence. And surely we can no more be free if determinism is false and it is, ultimately, either wholly or partly a matter of chance or random outcome that we and our actions are as they are.”
Neither determined nor random will afford any place for free will. Neither determinedness nor randomness (nor any mixture of the two) can give or allow what is wanted, even though between these two the field of possibilities is exhausted. Therefore, contrary choice or “free will” not only does not exist but cannot exist. 
