Who should I believe, when it comes to the Christian faith...?

Believe the Word of God,for in it it is the key to life, which is and always will be Jesus Christ.Faith though is an action word and produces fruit.If we say we believe the Word of God,then there ought to be fruit that shows in our lives that this is true.A person confessing Christ,but living in sin is not really a christian,but no different than the devil and his angels which believe also!