In much of present-day evangelism it is assumed that the one thing man can do in the exercise of his own liberty is to believe in Christ for salvation. It is supposed that this is the one contribution that man himself must make to set the forces of salvation in operation and that even God himself can do nothing towards this end until there is this crucial decision on man’s own part. In this assessment there is total failure to reckon with human depravity, with the nature of the contradiction that sin involves. Paul tells us that not only is the mind of the flesh not subject to the law of God but also that it cannot be (Rom. 8:7). This impossibility extends to the gospel as well. It is the implication of Paul’s other word that “the natural man does not receive the things of the Spirit of God, for they are foolishness to him, and he cannot know them, because they are spiritually discerned” (I Cor. 2:14). But to this truth we have the most pointed and express witness of our Lord himself. “No man can come unto me, except the Father who hath sent me draw him” (John 6:44); “no man can come unto me, except it were given to him of the Father” (John 6:65). Here is the witness of him who knows what is in man and who knows the Father as the Father knows him. And it is to the effect that it is a moral and spiritual impossibility for a man to come unto him except by the free gift from the Father in his secret and efficacious drawing.

The foregoing words of our Lord must be coordinated with another in the same context. “All that the Father giveth me shall come unto me, and him that cometh unto me I will in no wise cast out” (John 6:37). The giving on the part of the Father in this text has been understood as the election in Christ before the foundation of the world (cf. Eph. 1:4, 5) or, at least, in terms of giving to the Son correlative with or flowing from the election. But this does not by any means appear to be the action of the Father referred to in the text. There are two reasons for this conclusion. First, in this Gospel elsewhere, when Jesus speaks of those given to him by the Father, they are identified as those given to him out of the world, as those who had kept his word, as those who had known that all things given to him were from the Father, as those who had received the words given him and had come to know the truth that he, Jesus, had come out from the Father (John 17:6-8). These characterizations require much more than election before the foundation of the world; they involve a relation of faith. Second, in the more immediate context Jesus is referring to the effectual drawing and giving on the Father’s part (John 6:44, 65). So we must conclude that the giving is the giving that occurs in the actual operations of grace, defined more specifically as drawing and giving in the realm of consciousness. The constraints of the Father’s grace in the hearts of men are concomitant with or, perhaps, may be construed as donation on the part of the Father to the Son. God the Father draws men, places holy constraints upon them, calls them into the fellowship of his Son, and presents them to Christ as trophies of the redemption Christ himself has accomplished.

This constraint has been called “efficacious.” No other inference could reasonably be drawn from John 6:44, 45 Jesus is speaking of coming unto him, that is, of the commitment of faith and of the impossibility apart from the Father’s drawing. In making the exception it is surely implied that when the Father draws the exception occurs— the person drawn does come. Furthermore, it would offend against all that may be conceived as to the nature and intent of the Father’s drawing and giving in terms of verses 44, 65 to think of these actions as ineffectual. But John 6:37 puts this beyond all question: “All that the Father giveth me will come to me.” Jesus does not say: all that the Father giveth me are brought to me. He uses the term that denotes motion on the part of the person—”will come to me.” Coming to Christ is the movement of commitment to Christ, coming that engages the whole-souled activity of the person coming. It is not that he may come, not that he has the opportunity to come, not that he will in all probability come, and not simply that he is empowered to come, but that he will come. There is absolute certainty. There is a divine necessity; the order of heaven insures the sequence.

https://www.the-highway.com/Irresistible_Murray.html