Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me. Behold, I stand at the door and knock - There are many sayings of this kind among the ancient rabbins; thus in Shir Hashirim Rabba, fol. 25, 1: "God said to the Israelites, My children, open to me one door of repentance, even so wide as the eye of a needle, and I will open to you doors through which calves and horned cattle may pass."
In Sohar Levit, fol. 8, Colossians 32, it is said: "If a man conceal his sin, and do not open it before the holy King, although he ask mercy, yet the door of repentance shall not be opened to him. But if he open it before the holy blessed God, God spares him, and mercy prevails over wrath; and when he laments, although all the doors were shut, yet they shall be opened to him, and his prayer shall be heard."
Christ stands - waits long, at the door of the sinner's heart; he knocks - uses judgments, mercies, reproofs, exhortations, etc., to induce sinners to repent and turn to him; he lifts up his voice - calls loudly by his word, ministers, and Spirit.
If any man hear - If the sinner will seriously consider his state, and attend to the voice of his Lord.
And open the door - This must be his own act, receiving power for this purpose from his offended Lord, who will not break open the door; he will make no forcible entry.
I will come in to him - I will manifest myself to him, heal all his backslidings, pardon all his iniquities, and love him freely.
Will sup with him - Hold communion with him, feed him with the bread of life.
And he with me - I will bring him at last to dwell with me in everlasting glory.