Jesus spent much of His Sermon on the Mount preaching about the Kingdom.  What's the Kingdom like?  What are the unique realities that belong only to those in the Kingdom?  Are there promises to those who live in the Kingdom?  And, if so, what are they?  How does one receive the Kingdom and, more importantly, how does one enter into the Kingdom?
The key is found in Mark 10:15:  “Assuredly, I say to you, whoever does not receive the kingdom of God as a little child will by no means enter it.”
Did you catch that?  Receiving must precede entering when it comes to the Kingdom.  Do you want to know more?  Then keep listening.
The following is a study on Matthew 5:19.