The Nationality of the Christian
In "Biblical Perspective" Larry Grile writes:
Peter considered Christians to be of a different “nationality.” In this world we are not at home; we are foreigners merely passing through to our native country. Abstain from fleshly lusts. God has created us with desires; but sin has tainted human desires with a compulsion to selfish, sensual, and illicit expression. While that compulsion may be purified from the heart, it remains that the capability of desires is still there and must be brought under the control of the Holy Spirit, who alone can help us to keep ourselves within proper bounds. To what extent any individual Christian may, for example, momentarily admire beauty, etc., within sanctified bounds will depend on each person's vulnerabilities; only the Holy Spirit can guide each person in drawing these lines. Nevertheless, it remains that such desires are themselves potential mortal enemies to all that is right and good in our hearts and lives, until and unless they are kept continually surrendered to God. This issue does not represent a single battle, but rather is a potential warfare that continues as long as we live; the man who lets down his guard of faith, prayer, and self-discipline will find himself a victim of the devil.
Source: Building Christian Relationships: Adult Teacher's Insights, page 76.