I believe these kingdoms are at war on the earth today.
The Kingdom of God has already secured the ultimate victory, but his enemy is unwilling to lay down his arms and peacefully surrender. He wants to cause as much damage as he can before he is destroyed permanently.
The kingdom of his enemy does not require any oaths or commitments. Everyone is by default a citizen of this kingdom from birth.
The Kingdom of God requires one to commit their life to the service of the King and renounce their citizenship to the kingdom of the enemy. It requires one to lay down his or her plans, desires and purposes and instead work only at the command of the King.
It does not require effort to advance the kingdom of God’s enemy, because disunity and confusion advance his purposes. Everyone may set their own agenda: money, power, comfort, religiosity, sex; these are all common individual purposes in the kingdom of the enemy.
It is also the reason that the enemy’s kingdom will not stand. It has no unified purpose other than to consume all that it comes in contact with. It is at war with itself all the time.
As as the Kingdom of God unifies behind the King - not behind a particular denomination or doctrine - he leads us in a great campaign of sabotage against the enemy. He sent his son to lead our campaign: “the Son of God came to destroy the works of the devil” (1 John 3:8)
Our purpose is two fold: to press back the advancing lines of the kingdom of the enemy from his attempts to rule over the people of this earth, and to rebuild what his army has destroyed. He uses a slash and burn campaign, destroying anything he cannot have.
We share the secret that anyone in the kingdom of the enemy is free to defect. The miserable existence they lead now under the oppression and infighting of the enemy can be left behind. The Kingdom of God is exclusive in so far as it is only for those who will stand with the King.
I serve at and for the pleasure of the King. And by my life or my death, I will advance his kingdom on this battleground called earth.
I don’t do this in my own strength, but in his. For unlike the kingdom of the enemy, who only takes from his denizens, our great King actually puts his life into us. He doesn’t make us hired soldiers. He makes us sons and daughters. He adopts us.
I stand with the King.