All that the Father gives me will come to me, and whoever comes to me I will never cast out. – John 6:37
The words of John 6:37 reveal the purpose of the Father in giving his elect Jesus Christ. The Father’s purpose was that they might come to him and be saved. This, says the Son, shall indeed be done. Sin, Satan, the flesh, or the world shall never hinder their coming to Christ. The Lord Jesus positively determined to perform such a sufficiency of grace, that it will effectually perform this promise, and use all of the means necessary to accomplish this purpose. The Father’s end will not be frustrated (John 6:39). By coming, we understand it to be the coming of the mind to him, and the moving of the heart towards him. It is a coming with an absolute desire to be justified and saved. There needs to be the sense of a lost condition to move him to come. This made 3000 come; it made the jailor come; and indeed makes all others come effectually. Death is before them and they see it and feel it, and it feeds upon them, and eat them quite up if they do not come to Jesus Christ. They come of necessity, being forced into by the sense they have of their being utterly and everlasting undone, if they do not find safety in him. “Come to me, all who labor and are heavy laden, and I will give you rest” (Matthew 11:28). This coming to Christ is a running to him, a flying to him from the wrath to come. When all refuge fails, and man is made to see that there is nothing left in him but sin, and damnation, unless he flies to Christ for life; then he flies, and not until then. There is a sense of absolute need of Jesus Christ: “Lord save me or I perish!” There is an honest and sincere forsaking of all for him: “Whoever does not bear his own cross and come after me cannot be my disciple.” (Luke 14:26-27). He who truly comes must forsake all, cast all behind his back and cling to Christ Alone.
-John Bunyan
The Fight of Faith 