How do you defile the temple of the Lord?
Our body is already defiled and is subject to corruption.
Our body will be redeemed at the appearing of Christ. It will be translated from corruptible to incorruptible.
So what is Paul speaking of in this verse?
He is talking about our faith in Christ Jesus.
A person defiles what the Lord has made of them in the NewBirth by renouncing their faith.
Such will be destroyed.
This understanding is verified in the subsequent verses as Paul talks about deception and wisdom.