Behold, I stand at the door and knock. If anyone hears my voice and opens the door, I will come in to him and eat with him, and he with me.
God speaks with sinners through his messengers. They come for God’s purpose, and their words, counsels, exhortations, and reproofs are his. When sinners reject the words which God’s ministers bring in his name, they are actually striving with the Spirit. They are wrestling with Christ as if he were present. When God comes to reckon with sinners, it will prove just so. God will remind them of his striving and their unkind resistance. The Spirit strives with the consciences of men, debating in their own hearts the case against them, and shows man his sin in all its ugly colours. He does this so well that the creature can sometimes smell the very fire and brimstone about him, and makes him feel at present in a temporary hell. At other times, he parleys and works with them, and makes gracious overtures and offers of the gospel to them. He opens a door of hope and woos and beseeches them to throw down their rebellious arms and come to Christ for life. He reveals how Christ is in a present disposition to embrace their first motion towards mercy. The Spirit follows the sinner from place to place, and from time to time suggesting such encouragements. Many, however, cast off the Spirit’s hands in resistance. This carries such malignity in it, that some have felt the horror of the unpardonable sin, even though their condition is not final. Take heed, however, sinners how you respond to the Spirit when he comes knocking at the door of your hearts. Open at his knock, and he will be your guest; you will have his sweet company. Repulse him, and you have not a promise he will knock again. If once he stops striving with you, unhappy man, you are lost forever. Without the Spirit you lie like ship on dry ground. It is the Spirit that is both the tide and the wind that sets the soul afloat to carry it on.
Willam Gurnall, The Christian in Complete Armour, 1:116-117