“Answer. It is granted that to punish men for doing what they cannot help, or to require of them an impossibility, would be manifestly unjust and cruel. But this God does not, do. He requires no more of men than, they are able to perform; and he punishes them only for doing those things which they could and ought to have abstained from doing. When we speak, in common language, of ability and inability, can and cannot, possible and impossible, we always have reference to men’s power and faculties of body or mind, and not at all to their inclinations. If a man has all the power. and faculties of body and mind which are necessary to do a thing, we say he is able to do it, whether he is willing or not. His ability and his willingness are different things, perfectly distinct.
A man may be able to perform a piece of work, which he has no heart to perform, and which he is totally unwilling to engage in. And again, a man may be perfectly wiling to do that which is not in his power, that which is entirely beyond his strength. One man may be able to march to the field of battle, but totally unwilling. And another may be perfectly willing to march to the field of blood, but through bodily infirmity may be unable. Ability and willingness must both unite in the same person, before he will perform any thing, but they are perfectly distinct, and our willingness constitutes no part of our ability.
It is true that willingness is sometimes styled moral ability; but it is evidently in a figurative and improper sense. According to the usual and proper meaning of the term, men are able to do every thing which they have bodily and mental strength sufficient to do, whether they are willing to exert that strength, and do the thing or not. Now, although God cannot justly require of men more than they are able to do, that is, more than they have bodily and mental strength sufficient to do, if they were so disposed; yet he may, and does, justly require of them many things which they have no disposition to do, many things which they are totally unwilling to perform. And though men cannot be justly punished for not doing those things which they are unable to do, yet they may be justly punished for not doing those things which they are able, but are unwilling to do. Men are able to comply with the invitations of the gospel, that is, they have all the bodily and mental powers that are necessary to do it, and God may justly require them to do it, whether they are willing or not; and if they do not comply, he may justly punish them for their disobedience. And his making some willing and others unwilling, does not interfere with the ability of any. Those who are unwilling are just as able as those who are willing, and are as justly required to comply. To substantiate the objection, it must be made to appear, that God imposes some constraint upon men, so that they cannot do the things he requires, even though they are willing, and desirous of doing them. This is taken for granted in the objection. This is the real meaning of the phrase, doing what they cannot help. The meaning is, that they desire and endeavor to do otherwise, but have not the necessary bodily and mental strength. If they had, they should do, otherwise.
They would, but cannot. But the fact is directly the reverse. They can, but will not. They have the necessary bodily and mental strength, but have no willingness. And this, God is not bound to give them. Should any say, that God cannot justly require of men any more than he gives them a willingness to do, as well as bodily and mental strength, this would abolish all law, and destroy the distinction between right and wrong. For if God cannot require of men any more than he makes them willing, as well as able, to do, then, since they always do what they have both strength and will to accomplish, he cannot justly require of them any more than they actually perform. And if they always do all that he requires, there is no such thing as sin in the world. It is right, therefore, for God to require of them all that they have powers and faculties sufficient to perform, all that they are able to do; and if they fail of complying through unwillingness, it is right that they should be punished. But men have all the powers and faculties necessary to comply with the invitations of the gospel, and all the commands of God, and want nothing but a willingness. They can comply, but will not. When, therefore, God punishes them for not complying, he punishes them, NOT for what they could not help, but solely for refusing to do what they could but would not.”
~Williams Weeks, Nine Sermons on the Decrees and Agency of God, 3rd ed., (Newark, N.J.: Published by the Ecclesiastical Board of Trustees for the Propagation of the Gospel. John R. Weeks, Printer), 77-80. [Some spelling modernized and underlining mine.]