'Now this I say, brothers, that flesh and blood cannot inherit the kingdom of God. Neither does corruption inherit incorruption.'
He then emphasises that flesh and blood, our earthy body as it is, cannot inherit the Kingly Rule of God in its heavenly form, cannot come into God's presence as it is. What is corruptible and decaying, cannot as it is inherit a life which is incorruptible. There will therefore need to be a mighty transformation through resurrection. But this need for transformation also includes those living when Christ comes. They too cannot be taken as they are. They too must be transformed.
What then will bring about this change that means that earthly Christians can inherit their heavenly kingdom? It is by their bodies being made spiritual and heavenly, being made incorruptible, by the power of God. They will no longer be flesh and blood. They will be heavenly.