'So also is the resurrection of the dead. It is sown in corruption; it is raised in incorruption. It is sown in dishonour; it is raised in glory. It is sown in weakness; it is raised in power. It is sown a natural body; it is raised a spiritual body. If there is a natural body, there is also a spiritual body.'
'It' must in context refer to 'the body'. So the resurrection body, while connected with the old in some way, is totally new and unlike anything else we know. The dying and disposal of the old body is like the sowing and dying of a seed. The body is sown as a corrupt and decaying body. But what is raised is incorruptible and undecaying. It is sown in its humble earthly state, but what is raised is honourable and glorious. It is sown in a state of weakness, as a weak and frail body, but it is raised in power, as strong and vibrant and whole. It dies a natural (soulish) body, connected with the earthly creation, it is raised a spiritual body, connected with the spiritual world. Yet this must not just be seen as its spirit existing on. It has some kind of relationship with the previous body. Through Christ death results in new life for the body. But while emphasising that, he also emphasises the clear distinction between the two bodies. We must not expect to rise again as we are now. Our new form will be not liable to corruption, it will be honourable and glorious, powerful and spiritual. There will be no more disfigurements, no more disabilities, no more frailty, all will be perfected.
This might be seen as important with relation to the make-up of man. It suggests that the 'physical body' contains a spiritual element which is outside the range of science to discover, and is yet an integral part of the man's 'body', brought to life by his new birth in Christ by the Spirit, for it is that part which will form the basis of the new resurrection body.
We know a little of Jesus' resurrection body, but it would be dangerous to argue from Jesus' resurrection body to our own. Certainly His was not an ordinary body. He could come and go instantaneously. But it was necessary that it be recognisable and that the nail prints and spear wound could be seen, and that He be able to eat earthly food. Nothing of that will be necessary for the resurrection body of God's people.