Revelation 3:20 (ESV) … “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.”
It is one of the saddest pictures imaginable. In spite of so many evangelistic sermons about the need for people to open the door of their heart to let Jesus in so that they can become Christians, this is not the primary meaning here.
Jesus is speaking primarily to the church, though also to individuals within the church, and so he is speaking to those who at the very least consider themselves to be Christians. It is Christians to whom Jesus speaks here and whom he now rebukes. They must repent and involve him in their lives and mission and witness. If they do this, then Jesus says, I will come in and eat with him, and he with me.
Here again Jesus promises to come. He is not thinking at this moment of the final coming of Christ but of a ‘coming’ in which he will once again bring them his blessings and his fellowship and presence with them—I will come in and eat with him, and he with me. The meal is a symbol of the restoring of full and close communion between the Lord and his church.
This promise is for the whole church and the call is to the whole church. But Jesus has made the appeal in the singular (If anyone hears), and it may well be that only a few will respond to this call and so receive the promises. It reminds us that we come before God both as part of a local church but also as individuals responsible to him for our own service and commitment.
 Gardner, P. (2002). Revelation: The Compassion and Protection of Christ (p. 65). Ross-shire, Great Britian: Christian Focus Publications.