The mark of a true Christian is genuine love for one another (Rom 12:9). Christians abhor what is evil according to the revelation received in the Holy Bible. Therefore, unlike unbelievers, Christians love one another in ways that are similar to their love for themselves and the Triune God. For example, would you allow yourself to go unnecessarily hungry? Surely, you would not allow yourself to go hungry. When you are hungry you feed yourself. A mark of a true Christian is that they provide for the needs of one another, because of the Spirit that God the Father has placed in our hearts to glorify the Lord Jesus Christ.