Let's take a look at five earmarks of authentic Christianity, taken from 1 John.
First, an authentic Christian confesses Jesus Christ as Lord (1 John 4:15). Christianity must begin with a verbal acknowledgment of Jesus Christ as the Lord of your life. The Bible says that even the demons believe and tremble (James 2:19). True Christians should be able to say that Jesus Christ is their Lord.
Second, if you are a true Christian, you will be unhappy or miserable when you're sinning (1 John 3:9). This doesn't mean you will never sin if you are a Christian (1 John 1:8). But there is a difference between recognizing that we will fail in some way, shape, or form in the future and going on a willful, continual track of sin. If you really are a child of God, you will have a sense of discomfort when you sin, because you know in your heart of hearts that what you are doing is wrong.
Third, an authentic Christian enjoys fellowship with other believers (1 John 5:1). A true Christian will want to be around other Christians. Those who isolate themselves from other believers do so at their own peril, because the Bible tells us that it is important to get together, encourage one another, and correct one another (Hebrews 10:24-25). After all, why should God go to your house if you won't go to His? A lot of us want all of the fringe benefits of Christianity without applying ourselves.
Fourth, an authentic Christian obeys the commands of Jesus Christ. If you are a true believer, then you will obey the commands of Jesus Christ (1 John 5:3). I will not deny that the Bible is filled with so-called rules, but their purpose is not to make our lives miserable. Rather, they protect us from potential harm. The person who blatantly and continually breaks the commandments of God simply does not know Him.
Finally, an authentic Christian loves and obeys the Word of God (1 John 2:5). You cannot effectively live the Christian life without a love for, and obedience to, God's Word. All true disciples of Jesus Christ will be students of Scripture and will walk according to its teaching. This is vital to authentic Christian living, because the Bible is indeed the very textbook of life (2 Timothy 3:16). Yet so many believers will not read the Bible. They don't realize that success or failure in the Christian life depends on how much of the Bible they get into their hearts and minds on a regular basis. We have to do it.
Taken from "Authentic Christianity" (used by permission).