Superlative: [O]f the highest kind, quality, or order; surpassing all else or others; supreme; extreme: superlative wisdom.

via Dictionary.com

It is almost a wrong label to call the Kingdom superlative.  It is Beyond that.  John the Baptist was the superlative of human attainment.  A life of solitude, of extreme separateness and consecration to the Lord was his.  Jesus gave the man this testimony, and the comparison to the Kingdom.

Truly I say to you, among those born of women there has not arisen anyone greater than John the Baptist! Yet the one who is least in the kingdom of heaven is greater than he.

Matthew 11:11

John was a man, a prophet, of the Old Covenant, under the law and order of Moses.  He signified the demarcation point between Old an New Covenants.  As the Law came through Moses, and Grace and Truth came through Jesus Christ, the exchange between the two marked the transition from the age of the Old Testament and the coming of the Messianic Age.

The Law and the Prophets were proclaimed until John; since that time the gospel of the kingdom of God has been preached, and everyone is forcing his way into it.

Luke 16:16

The issue is not that the Kingdom is better, the Kingdom is not of this world.  It is not of the highest kind or quality, for it is definitely not of the kind or quality of the world.  John was the superlative, the best, but the least in the Kingdom is better than that, for the Kingdom is not of that.  It supersedes on every level by being from above, and not beneath.

As the Lord spoke in the old times that His were so far above ours as the heavens are above the Earth (Isaiah 55:9), so He has made us now to be partakers of His divine nature through His precious and magnificent promises (2 Peter 1:4).  He has given us a new heart, removing our heart of stone, and giving us a heart and spirit (Ezekiel 36:26).  This is not the old way anymore.  As the Holy Spirit came upon men at various times in the past, He has come to live in the heart of the believer.  We are no longer “mere men” (1 Corinthians 3:4), but rather new creations in Christ (2 Corinthians 5:17), of which has not existed on the Earth prior.

The essence of this is that we who believe, having gained access through faith to this grace in which we stand (Romans 5:2), it is that we live today by the power of a greater Spirit within us, His Spirit, the Holy Comforter, God Himself.  Whereas in the Old Covenant, man had to rely solely upon himself, today, through the power of the Spirit, we can put off our old man, the old person who we were, and put on Christ, and live in His grace.  By trusting in the power of the blood to not only forgive us but the cross to change our nature, we can place our faith in the man Christ Jesus, and be changed.

The Kingdom is of a higher order.  And, while there is rank and position in the Kingdom (Matthew 5:19, Matthew 23:11), it is on a separate set of criteria than that of which man desires.

For the Kingdom consists of Righteousness, Peace, and Joy in the Holy Spirit (Romans 14:17), and whereas the flesh prizes achievement, the Spirit is our servant, loves always, and is pure, and the one who most wholly submits to Him, and who most completely becomes Jesus to the dying world (Exodus 7:1, figuratively), is the one that is the greatest in the domain of heaven and has the most of Him.

To live by the Spirit is to deny the self and to give no opportunity for the flesh.

Jesus came and presented His Gospel.  By it, men will live or die.  By it, men will spend either eternity in heaven or hell.  Man could do nothing, condemned (John 3:18) and dead in his sins (Ephesians 2:1).  Yet He came and demanded that men hate their lives, love no one more than Himself, and that they forsake everything in their lives to follow Him.

Jesus was not looking for mere compliance, He demanded absolute submission based on trust and faith from those who would be His disciples, and even in that chosing, He had degrees (even as He picked twelve out of the masses, and sometimes just three of those).

If it wasn’t for a the fact that this is an Eternal realm, a place of everlasting consequences, there  would be no mandate upon the evangelist.  Without the heaven and hell question, what would be the motivation to preach the truth of the Gospel, to live for Christ and not for sin?  But, it is there, and it does include the nature of the Kingdom.

The Kingdom is not of this world.  It is of a higher order in every dimension.  It exists alone, above the heavens, as pure and holy and untouchable as the finished work of Christ itself.  It exists in the domain of God, and has its throne upon the crystal sea.

There is no stopping it.

You can either be for it or against it, but there is no middle ground.

That which is flesh is flesh, and that which is spirit is spirit.  We are commanded to hate the flesh, that we will hate one and love the other.  The truth of the scriptures is that He wants us to be like Him (John 1:12).  The choice is up to us.  We can be saved, and still live wrong, and guarantee no lasting reward.  But, to be fully submitted to the Holy Ghost is to live by His Spirit within us, and, as it should be absolutely evident throughout history, not everyone does this.

If you relegate the entirety of the choice of how much to pursue to Jesus and His grace alone, you negate the real question of your soul.  If you matter at all, yes it is Christ’s power within you, but we are responsible for what we are given.  We are not saved by works, but we are rewarded, promoted, and even preserved by our obedience.

The Kingdom is of a higher order.  Above every system of the world, and every thought of man, it is higher.  As high as the heavens are above the Earth, so are we now in Him.

The limit is our faith (Romans 12:6).  For, we have the mind of Christ, and the Spirit within us searches all things, even the deep things of God.  While it may not be apparent in the life of every believer that we have all knowledge, this is what is available to us, every day, simply because we are of Him, if we can only believe (1 Corinthians 2:10-11).

With a cost of absolutely everything (Luke 14:33), this Kingdom is still absolutely worth it.  As a treasure hidden in a field, selling all to buy is always “for joy” (Matthew 13:44).

Because to simply be of His Spirit fully, all the time, which requires forgiveness and seeking after Him, is to be greater than the greatest of man of God from the Old Testament.  To be the smallest door-keeper within His Domain is to succeed greater than the most powerful unsaved person in the world.  To be of Him is to be His child, to be a servant, and to know love, which is greater than anything else in the created order, on par in strength with death itself.

Put me like a seal over your heart, Like a seal on your arm. For love is as strong as death, Jealousy is as severe as Sheol; Its flashes are flashes of fire, The very flame of the LORD.

Song of Songs 8:6

You will not put out this love, this Kingdom.  You will not stop it.  If you try to preserve your life, you will lose it, but if you lose your life for Him, you will find a greater existence.

To live any other way is death, even if in the end you ‘survive’ (1 Corinthians 3:10-15).