Revelation 3:20 Behold, I stand at the door and knock: If anyone hears My voice and opens the door, I will enter to him, and I will dine with him, and he with Me.
Revelation 3:20 is a beautiful text. When you read the texts around it, you see a God who is talking to people who believe in God, but who are not walking with God, or fellowshipping with God. They became lukewarm Christians. God says how He feels about these people. He says He's about to vomit them out of His mouth. But then as you read on you see a God who also says He loves these people. He asks them to repent. And then He says that instead of walking away from them, He stands at the door and knocks.
The word “stand” is used in the sense to establish, to stand immovable, or to be of a steadfast mind. So the picture we have is a God who loves the people He created. It sickens Him to see them going on with life, without taking time to daily fellowship with God. The people have become selfish. They aren't listening to God and following His directions for them. But He loves them anyway. He wants them to be saved. So He plants Himself at the door, which would be the door to a person's heart. Or another way to say it is the door to their life. God wants to be a part of their life. He stands at the door and keeps knocking. He's knocking and waiting for an answer.
God doesn't just knock once or twice, He does everything He can to get a person's attention. He's persistent. His persistence is the result of His deep unconditional love for each person. But it's up to the person to respond. God never pushes His way in and forces a person to follow Him. He wants us to love Him willingly and follow Him willingly. God doesn't want puppets. He wants real people who love Him and spend each day walking with Him because they want to. He wants the love and the desire to be with Him to be real.
The way to open the door is to repent. A person just needs to start praying and telling God they realize they've been living without Him and know they've been wrong in living like that. Then they just have to ask God to take over in their life. Every day we have to ask God to be in charge of our lives and help us hear His voice as He guides us through the day. Some days we have to ask that several times a day because there's a tendency to still want to wander off on our own way.
Living apart from God is not something that only drunks, murderers, thieves, adulterers, and people of other such nasty lifestyles, do. Any time a person gossips, loses their temper, acts selfishly, manipulate others, anything that is not Godly behavior is living apart from God. When we separate ourselves from God like that, He's quick to come knocking and do anything He can to get our attention. And He keeps at it until He finally gets it. Throw that door open and let Him come in!