'And as we have borne the image of the earthy, so let us bear the image of the heavenly.'
That being so, says Paul, consider how it should change our whole attitude to life. When we bore only the image of the earthy and were in Adam it was natural that we would behave in an earthy fashion. But now that we are united with the One Who has heavenly life, and Who has imparted to our mortal bodies that heavenly life so that we bear the image of the heavenly, how different we should be. In those who are in Christ all should see the image of the heavenly in their mortal bodies, for they will behave like Christ. And in the end at the resurrection that image of the heavenly will shine through to such an extent that it will become all prevailing, so that as we ourselves originally bore the image of the earthy, so on resurrection we will bear the image of the heavenly to its fullest extent, and will be spiritual and glorious and Christ-like.
An alternative rendering of the second section is ‘so shall we bear the image of the heavenly'. But all the best manuscripts apart from B, both Eastern and Western, support the above reading, and it is the harder reading. We can therefore see no grounds for not accepting it as the original.