“So, then, what is this effectual, internal call that we are speaking about? Well, the most we can say about it is — and this must of necessity be true in the light of these scriptures — that it is the exercise of the power of the Holy Spirit in the soul. It is a direct operation of the Holy Spirit within us. It is immediate, it is spiritual, it is supernatural, miraculous. And what it does is to make a new mode of spiritual activity possible within us. Without this operation we are incapable of any true spiritual activity but as the result of this operation of the Holy Spirit upon us, we are rendered capable, for the first time, of spiritual activity and that is how this call now becomes effectual, that is what enables us to receive it.
“Now this is very important and I want to emphasise the immediacy, the direct action. You see, what happens when the call comes to men and women effectually is not simply that the moral influence of the truth is exercised upon them. Some people have thought that; they have said that the gospel is preached and that the truth has a kind of general moral effect upon people. For instance, to take a human theme, a capable orator, a man wanting to persuade men and women to vote at an election for a given party, can put the case so well that he can exercise a moral influence upon his listeners. But it is not that. It is an operation of the Spirit upon the men and women themselves, in the depths. It is not merely that the Holy Spirit heightens our natural faculties and powers, it is more than that. It is the Spirit acting upon the soul from within and producing within us a new principle of spiritual action.
“Now it must be that; it cannot be less than that. Because these things, says Paul, are all spiritual. And that is why the natural man does not understand them; and that is why, as I have often reminded you, we should never be surprised, or to the slightest extent disappointed or put out, when somebody brings us the argument that ‘Christianity cannot be right because look at this great man and he doesn’t believe it!’ How often have you heard that argument! Someone says, ‘You know, I cannot believe this, because if Christianity were true, it could not be possible that all these philosophers and scientists and all these great statesmen and other men do not believe it.’
“In the light of these things, it is very natural and we can understand it perfectly well. The greatest natural intellect cannot receive this, he is ‘a natural man’. And you need a spiritual faculty to receive the wonderful truth about the two natures in the one Person; the outstanding doctrine about the Trinity; the whole doctrine of the incarnation and the atonement, and so on. This is spiritual truth and to the natural person it is utter folly, it is foolishness, as Paul says. So when the Holy Spirit does enable us to believe it, it must be something beyond the heightening of our natural faculties. It is not simply that He brings the truth of His great moral suasion to us. No, no. We need some new faculty, some new principle, and that is the very work that He does. He implants within us this new spiritual principle, this principle of spiritual vitality and activity, and it is as the result of this that the general call of the gospel comes to us in an effectual manner.”
— Martyn Lloyd-Jones, “Effectual Calling and Regeneration”