Hosea 4:6
This verse is a powerful one for those in our churches who resist sound doctrine.  So many times doctrine and theology are condemned as divisive and narrow-minded.  As we reject the truth of the Scriptures in favor of a "religious" experience, we will find a greater emptiness in our worship of the Lord. 
Knowledge of and obedience to the doctrines, law, and guidelines is the basis for any successful Christian living.  We cannot just pick and choose what we wish to obey.  We cannot subjectively go through the Bible and select those things that work for us and forget those that don't.  And we most assuredly cannot subject the Bible to our reasoning and say that its rules are antiquated or irrelevant. 
As Christians, we must unquestioningly obey all the regulations God places on our lives.  We dare not presume upon His grace with flippant little justifications like, "I couldn't help myself", "It's not that bad", or "God will understand."  Those who make such rationalizations do not seem to realize that it was our sin that nailed Jesus to the cross.  How can we flippantly dismiss that which did such hideous things to our Lord.  It is no wonder God's people are being destroyed for their lack of knowledge.