Dear hosepipe, Christianity early on dealt with that sort of platonic dualism with the early Gnostics. The first thing I would point to is that when God created the universe, including man, he declared it was very good. There is nothing inherently bad about the human body. That is part of who we are. When sin entered it effected the body but it also affected the spirit. Sinfulness affects the spirit just as it effects the body and even for those who come to a knowledge of what redeems both body and spirit they are still left with the affects of sinfulness to the spirit short of glory. We know that once we attain glory we shall be reunited with our bodies and our body and spirit shall be perfected just as it was with the original man and even moreso.
One of the major errors of the Gnostics was their claim that Jesus did not really come in the flesh and this is a natural consequence of Platonic dualisms. If the flesh is all bad and Jesus is all good then it would be inconsistent to claim that Jesus came in the flesh. But Jesus did come in the flesh to redeem the whole man not just his spirit otherwise he would not have been incarnated. I'm afraid your reading of Jesus in his depiction of the flesh and spirit is too literal and does not take into account that his reference to flesh does not refer to the organic substance per se but the results that sinfulness has upon man's thinking and feeling and willing such that his actions are directed towards himself as a whole being first and not directed towards God who is spirit and the source of man and from whom we receive all wisdom. If we take this view then we can rejoice in our bodies and souls as one being created by God as very good in its original constitution and being redeemed as a whole being we can put our being in service to God as that for which we were originally designed.
What I posted seems to have gone completely over your head..
I didn't say the flesh is "bad" just temporary..
Some mentalities have a real problem considering a better life when flesh is not included.. That flesh is somehow required.. even preferred..
Humans are and have been virutal slaves to their bodies FIRST and some are slaves to other humans on top of that.. Humans must groom, feed, water, bathe, pay attention to gender niceties, breed, educate, heal, comfort, heat, cool, clothe, shod, protect, entertain, and at least a hundred other things before they serve other humans.. They are slaves because of their bodies.. You know their flesh.. And if you have a family you may be a slave to others too in many other ways..
All because a human body is so needy.. Gnostics saw "matter" as evil.. but I'm talking of the human body.. The human is a blessing for the ability to have our spirit tested... But almost everything else is a trial producing slavery to it.. Unless you starve or punish it.. in that case, that human, has mental problems..
Jesus never used the word heretic.. unless he implied it to various clergy of the times..