The kingdom of God is like a mansion with door, corridors and stairs. Coming into the kingdom is relatively easy, the door is open for everyone. It requires little effort on your part. You can walk straight in but once inside if you want to go through any of the other doors to any of the other rooms then you have to knock. You can just stay in the corridor if you wish but His desire is to explore. There are many doors to go through.
He wants you to experience His kingdom, to go through each of the doors you come to. There are some that take you up stairs and to places you never thought possible. You cannot force your way through, knock and it will open. Be persistent, don’t give up. You cannot just open the doors, He opens them for you. He invites you to knock. God wants you to experience and explore every aspect of His kingdom but it has to be through Him and on His terms.