Christians reject Gnosticism (the false dichotomy of spirit and body) for several reasons.  God made the physical world and declared it good.  Jesus came into the world as God incarnate, declaring again that the physical is good.  Even the physicality of the Lord’s Supper declares Christ’s presence in the bread and wine.  Not only are our hearts/spirits to be made holy now, so is our body!  Full and final redemption is the resurrection of the body.  God promises that this good creation will blossom into glorious new creation.  What a glorious hope!

“For we know that the whole creation groans and suffers the pains of childbirth together until now.  And not only this, but also we ourselves, having the first fruits of the Spirit, even we ourselves groan within ourselves, waiting eagerly for our adoption as sons, the redemption of our body.” Romans 8:22-23 (NASB)