1 Corinthians 6:19-20 Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? You are not your own, for you were bought with a price. So glorify God in your body.
God cares about what you wear and how you represent Him within the body of Christ. You were chosen as an ambassador of Christ. Therefore, how people view you as a Christian affects their view of Christ.
Romans 12:2 Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.