There are many that profess to be disciples of Jesus of Nazareth, yet their actions and beliefs contradict the Word of God. So if one's belief contradicts the Bible then where did their belief come from, after all their Christians. I've talked to many people who call themselves Christians yet beliefs they have contradict the scriptures and when it's pointed out to them the response is "that's what you believe, I believe something else". My question is "where then does your belief come from?". Man made teachings have filled the Church and so many have been lead astray, and yes, you can be lead astray. Jesus, God Himself, warns us in John 16:1. While many may believe in Jesus, He tells us our faith requires more if we wish to enter His Kingdom, that many that believe in Him will not enter. Knowing these things one must make sure that their belief is in the scriptures and not in man made teachings. I revisited What Do You Believe, talking about false prophets and teachers. The bottom line is we must take the whole Bible for what is says and not try to find ways out of being obedient to Jesus.
And have no fellowship with the unfruitful works of evil, but rather expose them.