23.  Tell me not that the body is a cause of sin Fortunatus, the Manichee, in August. Disput. ii. 20, contra Fortunat. is represented as saying, What we assert is this, that the soul is compelled to sin by a substance of contrary nature..  For if the body is a cause of sin, why does not a dead body sin?  Put a sword in the right hand of one just dead, and no murder takes place.  Let beauties of every kind pass before a youth just dead, and no impure desire arises.  Why?  Because the body sins not of itself, but the soul through the body.  The body is an instrument, and, as it were, a garment and robe of the soul:  and if by this latter it be given over to fornication, it becomes defiled:  but if it dwell with a holy soul, it becomes a temple of the Holy Ghost.  It is not I that say this, but the Apostle Paul hath said, Know ye not, that your bodies are the temple of the Holy Ghost which is in you 1 Cor. vi. 19.?  Be tender, therefore, of thy body as being a temple of the Holy Ghost.  Pollute not thy flesh in fornication:  defile not this thy fairest robe:  and if ever thou hast defiled it, now cleanse it by repentance:  get thyself washed, while time permits.