Paul in the epistle to the Philippians alludes to two citizenships, one earthly and one heavenly: "Their mind is set on earthly things. But our citizenship is in heaven" Philippians 3:19-20.
This spiritual teaching about the two citizenship is an idea deeply rooted in the thought of the apostle Paul, let us remember that Paul was a Roman citizen and in the time of the emperors Roman citizenship was a privilege, some had it by birth but others bought it with large sums of money as the Bible explains in the Book of Acts:
"The commander went to Paul and asked, ´Tell me, are you a Roman citizen?´
´Yes, I am,´ he answered.
Then the commander said, ´I had to pay a lot of money for my citizenship.´
´But I was born a citizen,´ Paul replied" Acts 22:27-28.
Having a citizenship in practice can mean that we have some rights and not others, and this also happens with obligations. And this in spirituality is of the utmost importance, because when we have heavenly citizenship, we receive a special right and it is the promise of eternal life, the contemplation of the divine attributes of God: "This is eternal life that they may know you the only true God" John 17:3. The spiritual and the worldly are profoundly opposed in the doctrine of the Kingdom of God. When we live according to the dictates of the world or of the flesh, apparent goods leave us with a deep void, the meaning of life only appears when our neighbor matter: "Do unto others as you would have them do unto you", Matthew 7:12.
Paul invites us to leave that citizenship that condemns us to the works of the flesh and to enter the life of the children of God, through the spiritual gifts and the divine mysteries: "And we eagerly await a Savior from there, the Lord Jesus Christ, who, by the power that enables him to bring everything under his control, will transform our lowly bodies so that they will be like his glorious body" Philippians 3:20-21.