“There are two principal ways, by which Christ opens the understanding and hearts of men, viz by his Word and Spirit.”
1. “By his Word; to this end was Paul commissioned and sent to preach the gospel, Acts 24:18, “To open their eyes, and turn them from darkness to light, and from the power of Satan to God.” The Lord can, if he pleases, accomplish this immediately; but though he can do it, he will not do it ordinarily without means, because he will honour his own institutions. God will keep his ordinances among men: and though he hath not tied himself, yet he hath tied us, to them.”
2. “But the ordinances in themselves cannot do it; and therefore Jesus Christ hath sent forth the Spirit, who is his vice-regent, to carry out this work upon the hearts of his elect. And when the Spirit comes down upon the souls in the administration of the ordinances, he effectually opens the heart to receive the Lord Jesus, by the hearing of faith. He breaks in upon the understanding and conscience by powerful convictions and compunctions so much that the word John 16:8 imports, “He shall convince the world of sin;” convince by clear demonstration, such as enforces assent, so that the soul cannot but yield it to be so; and yet the door of the heart is not opened, till he has also put forth his power upon the will, and, by a sweet and secret efficacy, overcome all its reluctions, and the soul be made willing in the day of his power. When this is done the heart is opened: saving light now shines in it; and this light set up, the Spirit in the soul is,”
1. “A new light, in which all things appear far otherwise than they did before. When he comes to read the same Scriptures, which possibly he had read a hundred times before, he wonders he should be so blind as he was, to overlook such great, weighty, and concerning things as he now beholds in them.”“And thus the Lord Jesus by his Spirit opens the understanding.” ~ John Flavel
2. “It is a very affecting light; a light that hath heat and powerful influences with it, which makes deep impressions on the heart. Hence they whose eyes the great Prophet opens, are said to be “brought out of darkness into his marvelous light,” 1 Peter 2:9. The soul is greatly affected with what it sees. The beams of light are contracted and twisted together in the mind; and being reflected on the heart and affections, soon cause them to smoke and burn. “Did not our hearts burn within us, whilst he talked with us, and opened to us the Scriptures?”
3. “And it is a growing light, like the light of the morning which “shines more and more unto the perfect day,” Proverbs 4:18. When the Spirit first opens the understanding, he doth not give it all at once a full insight of all truths, or a full sense of the power, sweetness and goodness of any truth; but the soul in the use of means grows up to a greater clearness day by day: its knowledge grows extensively in measure, and intensively in power and efficacy.”
*Taken from The Works of John Flavel, Volume 1 pages 136-138