I have two dogs living in me

Commentary

When a person receives Christ as his personal Savior, tremendous spiritual changes take place:
He is given a new standing called “justification.”He is given a new position called “sanctification.”He is given a new nature called “regeneration.” 
A Christian has an old nature from his physical birth and a new nature from his spiritual birth. A new convert one said, “I have two dogs living in me – a mean dog and a good dog. They are always fighting. The mean dog wants me to do bad things and the good dog wants me to do good things.  The one that wins is the one I feed the most!” The physical man needs food, and so does the new or spiritual man. “Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God” (Matt. 4:4). Unless a Christian spends time daily in the Word the spiritual man will starve. A Christian who feeds the new nature will have power to live a godly life (v. 9). Yielding to sin is a dead give-a-way of “The children of the devil” (v. 10). They profess one thing but they practice another. The devil tries to deceive God’s children into thinking that a person can be a Christian and still practice sin. John is saying that a true believer does not practice sin but a counterfeit believer cannot help but practice sin. We should love each other and not be like Cain who hated his brother (vv. 11-12)

Application

The big question to ask myself is - do I truly have the new nature or am I just pretending? Do I allow the old nature to control my thoughts or does the new nature rule me?