‘Behold, I am standing at the door and knocking. If any man hear my voice and open the door, I will come into him, and will sup with him and he with me.'
We must remember that these words are spoken by the Son of Man in ‘the Lord's Day' (Revelation 1:10). They obtain their meaning from words of Jesus while on earth.
In Luke 12:35-38 Jesus tells His disciples that they must ‘let your loins be girded about (the clothes tucked in to the girdle to make movement easier) and your lamps burning, and you yourselves like men looking for their Lord when he returns from the marriage feast, so that when he comes and knocks they may immediately open to him '. Then He will sit them down to supper and come and serve them (Luke 12:37).
is a clear reference to that parable. The Son of Man, Whom John saw standing among the lampstands, is pictured as having arrived and as standing and knocking at the door of this church so that He may come in and sup with them. ‘I am here', He says, ‘knocking'. But the inference is that they are not ready to hear.
So He next makes His plea to individuals in the church. If any one will hear His voice and open the door He will come in to him and they will eat together. In other words He wishes the church to see Him as on the verge of His coming in glory, and to respond on that basis. At some stage He will come, and no one knows when, so they must be like servants making ready.
But He recognises that they are so complacent that He is doubtful of their response so He then addresses each individual member. If any individual will therefore recognise Him as the coming Lord and welcome Him, even before His coming, He will sup with them, and they with Him. This does not really represent the heart's door, but it does refer to an individual's willingness to receive Him and welcome Him, which is much the same thing.
This reminds us that all these letters sent to the churches are sent as from the Lord Who is about to come in His glory. They are to see Him as on the verge of coming. As we learn here, this is in order to awaken them. It is also an encouragement to them to persevere in the face of hardship and tribulation. He is still on the verge of coming today. He delays only because He is longsuffering (2 Peter 3:9). But who knows when He will finally arrive?