Does that title sound contradictory? I can see why it sounds that way, but consider two profound things that Jesus said about John the Baptist,

“Assuredly, I say to you, among those born of women there has not risen one greater than John the Baptist; but he who is least in the kingdom of heaven is greater than he” (Matthew 11.11).

As far as what makes a man, John surpassed everyone, yet, John was not in the kingdom of heaven, which is the church on Earth. That being the case, he was least than even the lowest who is in the kingdom!

By this manner of speech, Jesus showed the greatness of John, but then showed that being in the kingdom of heaven is to experience something even greater than being John himself.