It Does Not Matter…
Why is this a “comfort doctrine”? 
Because it removes the need to accept what God’s word tells you to do.  
Simply stated, it can lead to the mentality that you formulate what you want to believe and do and then you find a church that allows you to do it.  
Thus you find comfort without total obedience to the truth.

What Does The Bible Say?
The need for unity is clearly taught in scripture.
1 Corinthians 1:10 – Paul’s admonition to a divided congregation.
John 17:20-21 – the prayer of Jesus.
Ephesians 4:1-6 – endeavoring to keep the unity of the Spirit in the bond of peace.

What Does The Bible Say?
What is meant by unity in the Bible? 
Unity in the Bible was NOT ecumenicalism.  
Nowhere do you read of this concept that we set aside doctrinal differences to achieve unity.
The Bible is clear that what God says IS TRUTH and as such must be taken at face value as truth.  

What Does The Bible Say?
John 17:17 – “Your word is truth”
John 16:13 as Jesus promised that He would send the Spirit to His apostles He said, “However, when He, the Spirit of truth, has come, He will guide you into all truth; for he will not speak of His own authority, but whatever He hears He will speak; and He will tell you things to come.”
Ephesians 4:21 says, “But you have not so learned in Christ, in indeed you have heard Him and have been taught by Him, as the truth is in Jesus.”

What Does The Bible Say?
John 8:32, “The truth shall make you free.”
When Pilate said, “What is truth?” (John8:38) he was dismissing the claim of Jesus that, “Everyone who is of the truth hears My voice.”
NOWHERE in scripture is truth treated as arbitrary.  
But we are told, “Therefore do not be unwise, but understand what the will of the Lord is.” (Ephesians 5:17)

What Does The Bible Say?
It is AGREEMENT in TRUTH that produces unity.
1 Corinthians 1:10 again - “All speak the same thing” and there were NO divisions.
1 Corinthians 4:17, “As I teach everywhere in every church.”  
Paul did not have a different message for Ephesus, Corinth and the churches of Galatia (Yes they were different letters with different topics addressed, but they were NOT contradictory. Wherever the same subject was addressed, there was COMPLETE harmony.)

What Does The Bible Say?
Even Peter and Paul were in agreement – 2 Peter 3:16.
To the Philippians Paul challenged them to be like minded.  He said, “Therefore if there is any consolation in Christ, if any comfort of love, if any fellowship of the Spirit, if any affection and mercy, fulfill my joy by being like-minded, having the same love, being of one accord, of one mind.” (Philippians 2:1-3)  
Yes that message was to one congregation, but the principal applies universally as the truth does NOT contradict itself.
Consider Galatians 1:6-9 written to SEVERAL churches and yet there was ONE message for all of them.

What Does The Bible Say?
Biblical principles to consider when one says, “It doesn’t matter what we believe.”
2 Timothy 3:16, 17 – “All scripture” is profitable for “doctrine, reproof, correction and instruction in righteousness.”
James 1:21-25 – we must look into and continue in “the perfect law of liberty.”
Matthew 7:21-23 – Not every who says ‘Lord, Lord’…  In essence Jesus said that there are those who claim to be Christians (i.e. believed in Him and thought they were obeying Him) who WILL BE LOST!  Those who will be saved are those who DO the will of the Father.

What Does The Bible Say?
Concerning false teachers.
Many who profess “it doesn’t matter what you believe” have a challenge in dealing with the matter of false teachers. 
Whether they admit it or not, they are by default accepting that (according to their beliefs) there are false teachers who will be saved.  
Since truth is absolute, when there are differing views, at least one party MUST be wrong.  
If he teaches what is wrong, he IS a false teacher! 
DOES the Bible tolerate false teachers or false teaching? The answer is NO!

What Does The Bible Say?
2 Peter 2:1-3 speaks of false prophets and teachers who will bring in destructive heresies.  Who is a false teacher? Multiple warnings against false teachers – many of whom believed in Jesus in some form.
1 John 4:1 calls for us to “test the spirits, whether they are of God.”  This is in a context where one is denying Jesus came in the flesh (NOT denying Jesus Christ).  
Does it matter what one teaches?  John said it did! (1 John 4:2-3).
2 John 9-11 – we find instructions as to how to deal with one bringing false doctrine.  Do not receive him.

What Does The Bible Say?
Acts 18:24-28 speaks of Apollos who had been instructed in the way of the Lord and taught it accurately EXCEPT he knew only the baptism of John.  To summarize, he was taken aside by Aquila and Priscilla and corrected.  When corrected he taught accurately.  
According to the doctrine of many today what Apollos was teaching was no big deal and should be tolerated.  IT didn’t need correction.
While there is some distinction in scripture between false teachers with dishonest motives and those who are honest teaching error, NEVER are false teachers or false doctrine treated as acceptable!

What Does The Bible Say?
Is the gospel exclusive?  Yes and No!
From the standpoint of the gospel being available to anyone and everyone, the answer is NO! Romans 1:16, John 3:16, etc.
However, from the standpoint of HOW one is saved and HOW we are to serve God, the answer is YES!  
2 Thessalonians 1:8 speaks of those who do not obey the gospel.
Luke 6:46, “But why do you call Me ‘Lord, Lord,’ and not do the things that I say?”
Romans 2:7 speaks of eternal life awaiting those who “by patient continuance in doing good seek for glory, honor and immortality.”
Matthew 7:13-14 – the narrow gate – few will find it.

What Does The Bible Say?
Some make a distinction between “gospel” and “doctrine”. 
In scripture the gospel IS doctrine.  
Consider the following:
1 Timothy 1:10-11, speaks of both “sound doctrine” and “the glorious gospel of the blessed God…”
In the book of Romans Paul describes WHAT we obey using 4 different terms -  Romans 1:5 – “obedience to the faith”Romans 2:8 – those who “do not obey the truth”Romans 6:17 – obeyed from the heart that form of doctrine.”Romans 10:16 – “But they have not all obeyed the gospel.”

What Does The Bible Say?
Doctrine is described as:1 Timothy 1:10 – “sound doctrine” 1 Timothy 6:3 – doctrine “accords with godliness”2 Timothy 3:16 – the gospel is profitable for “doctrine” which makes the “man of God complete.
2 John 9 speaks of “the doctrine of Christ”
Acts 2:42 speaks of “the apostle’s doctrine”
John 7:16-17 – Jesus noted that His doctrine was not His, but the Father’s
How can one say that gospel and doctrine are different things?

What Is Wrong With This Doctrine?
It is both unscriptural & anti-scriptural as we have seen.  
NOWHERE does the Bible dismiss false teaching.  
It is to be dealt with!
It makes the truth arbitrary.
This doctrine trivializes doctrinal accuracy.
It promotes division – by definition, denomination includes division.

What Is Wrong With This Doctrine?
It promotes ignorance – why study if it doesn’t matter?
It removes true accountability – if it doesn’t matter which church you attend, then why not find “the church of YOUR choice” that requires minimal change in your life?
Why contend for the faith? (Jude 3)  If a brother is in error, why go to him?  After all it doesn’t matter what we believe!
It redefines many Biblical terms - what the Bible teaches about grace, fellowship, what the gospel and doctrine is, who our brethren are and sin.

Conclusion
TRUE Comfort:
Comes through knowing the truth of God’s words – 1 Thessalonians 4:18, Romans 15:4, which means we need to study His word.
Comes through KNOWING we are doing it – i.e. obedience (Romans 2:8).
Comes through seeking TRUE and COMPLETE unity.
Comes by Seeking those of “like precious faith.”
Comes by doing God’s will in all things.
Are you comfortable with your spiritual condition?