NOTES for Co2 5:20-21
For Paul it is evident: the Kingdom and abiding in it are inseparable from the relationships that bind each of His followers to Christ, but these relationships themselves are possible only when a person remains in Christ to the end and completely poor, in the spiritual sense in which the prophet Isaiah of Jerusalem already spoke of poverty.
In that sense of the word, poverty carried to the end is nothing other than becoming nothing, even to physical death, if it is required for witness. And for the Messiah, it means even complete, unreserved, and unconditional immersion in the sinful life of the fallen world, into whose depth He had to bring the fullness of the Kingdom contained in Him.
And the evil of the sinful world truly takes the Messiah Himself captive. It cannot penetrate the depth of His heart or His human nature, which is free from the power of sin, but it was able to bring Him to the cross. The One who knew no sin came under the power of sin, became sin for our sake; this is how Paul describes it. Such is the poverty of the Messiah carried to the end, poverty without which the Kingdom would not have entered the world, because the Messiah Himself could enter the world in no other way than as a poor man.
This is understandable: any other entry would have meant submission to the laws of the world lying in evil. Not to submit to them meant to leave the world, but to leave the world while at the same time remaining in it means to die. Such a path for the Messiah, who bears in Himself all the fullness of God and all the fullness of the Kingdom, could end on earth only with the cross. And with the resurrection, of course, but that already belongs to the reality of the Kingdom, not of the fallen world.
A Kingdom to which the fallen world can belong only insofar as, being transfigured, it ceases to be fallen. We Christians become participants in this process, as the apostle reminds us. If we are alive and remain in this world, it is only insofar as the world itself has already ceased to be fallen, insofar as it has already had time to be transfigured and become part of the Kingdom. If the Kingdom were not in the world, only death would remain for us. Or life as the righteous lived, awaiting the Kingdom, in pre-Christian times. If, of course, we are Christians not only in name.