When Paul said that in his flesh dwelt no good thing, he was not calling his body evil. He was saying that there is a principle of sin in fallen man. The Hebrew writers refer to this as the evil inclination . Actually we are to rejoice in our humanity. With the Greeks the highest form of spirituality was to enter into a monastic form of living.
Monasticism comes from a root word which means to be alone .
He said it wasn't good. One of the Latin fathers went so far as to say that when a man and his wife have conjugal relations the Holy Spirit leaves the bedroom. It was this thinking that contributed to the celibate priesthood. Nowhere does the Bible teach that a celibate lifestyle is particularly spiritual. Actually it teaches the opposite.