The moon is pink yellow. The sky is neon. The earth is flat. I could choose to believe these things, but my sincerity would not validate my belief. I would still be wrong. But some say it doesn’t matter what you believe as long as you are sincere. I could sincerely believe I paid my taxes, but unless I actually paid my taxes I would be in trouble with the government. No amount of sincerity would keep me from paying a large penalty to the government.
The only field in which sincerity trumps truth is the postmodern approach to religion. Yet, we know that the nature of truth itself and the claims made by the Bible demand that either God and his word are correct or they are incorrect. As C. S. Lewis once deduced: Jesus is either a lunatic, a liar, or The Lord. He must be one or the other. If Jesus is a lunatic or a liar, then it doesn’t matter what he said. However, if Jesus is Lord then everything he said is all that matters. It matters what you believe.
God spoke of the truth which must be believed. In 1 Timothy 4:6 the Holy Spirit inspired Paul to write, “If you put these things before the brothers, you will be a good servant of Christ Jesus, being trained in the words of the faith and of the good doctrine that you have followed.” While much of contemporary preaching has been relegated to moralizing, the Bible exhorts God’s people to put a certain set of “things” or “doctrines” before the church. These “things” are learned from “the words of faith” and form “the good doctrine that you have followed.”
God spoke of untruths which are not to be believed. Paul’s second letter to Timothy reminds all God’s people of the necessity to “preach the Word” (2 Timothy 4:2). There is a particular thing, “the Word”, which must be preached. Not every idea falls into this category. Not every book falls into this category. 99% of all religious books are excluded from this category. The only “Word” which is to be preached is the Scripture breathed out by God (2 Timothy 3:16). It is the same Scripture which is described as the “sacred writings” (2 Timothy 3:15).
To emphasize again the exclusive nature of truth, Paul exhorted Timothy to “reprove, rebuke, and exhort, with complete patience and teaching” (2 Timothy 4:2). If one is to carry out these actions, it demands there is the truth which is the standard for all people. Furthermore, this one truth presented in God’s Word is contrasted with those who “will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions, and will turn away from listening to the truth and wander off into myths.” To abandon the Bible is equated with “turn away from listening to the truth and wander off into myths”.
God spoke of the truth which must be “held to”. Titus 1:9 describes the character qualifications for those who would serve as elders. One of the qualifications is that these men must “hold firm to the trustworthy word as taught, so that he may be able to give instructions in sound doctrine and also be able to rebuke those who contradict it.” The Bible is again presented as the singular truth. The Bible truth is “trustworthy”, “instructions”, and the standard by which men are rebuked.
The Bible does not present God’s people with the task of making helpful suggestions. The God of Heaven presents the church with the responsibility of preserving, presenting, and prescribing God’s one truth. 1 Timothy 6:3-4 says:
If anyone teaches a different doctrine and does not agree with the sound words of our Lord Jesus Christ and the teaching that accords with godliness, he is puffed up with conceit and understands nothing. He has an unhealthy craving for controversy and for quarrels about words, which produce envy, dissension, slander, evil suspicions, and constant friction among people who are depraved of truth, imagining that godliness is a means of great gain.
Many may submit to error, but all people are invited to enjoy the truth. “But as for you, teach what accords with sound doctrine” (Titus 2:1).
God spoke of truth through which He is pleased. 3 John 4 records the words of John with which every Christian parent would Amen–“I have no greater joy than to hear that my children are walking in the truth.” Surely this was the goal of Paul for his converts as well. Colossians 1:9-10 records his prayer:
And so, from the day we heard, we have not ceased to pray for you, asking that you may be filled with the knowledge of his will in all spiritual wisdom and understanding, so as to walk in a manner worthy of The Lord; fully pleasing to him, bearing fruit in every good work and increasing in the knowledge of God.
As these words are studied, one cannot help but understand that there is truth which God has graciously revealed to us and that through obeying that truth (1 Peter 1:22) one may obtain “spiritual wisdom and understanding”; “walk in a manner worthy of The Lord”; and bear fruit for him. Without God’s Word, none of these things would be possible (Romans 10:17; Hebrews 11:6).

Beliefs matter because of the Bible’s Author. 2 Peter 1:20-21 describes the origin of the Bible. Peter wrote:
And so we have the prophetic word confirmed, which you do well to heed as a light that shines in a dark place, until the day dawns and the morning star rises in your hearts; knowing this first, that no prophecy of Scripture is of any private interpretation, for prophecy never came by the will of man, but holy men of God spoke as they were moved by the Holy Spirit (NKJV).
God’s word isn’t the product of human thought. God’s Word is the revelation of God’s thoughts. This makes all the difference.
Since the Bible is from God, its teaching matters. Since the Bible is from God, it is truth. Since the Bible is from God, all people must weigh their thoughts and actions by that Book. Timothy was reminded of the importance of Scriptures in 2 Timothy 3:14-16:
But you must continue in the things which you have learned and been assured of, knowing from whom you have learned them, and that from childhood you have known the holy Scriptures, which are able to make you wise for salvation through faith which is Christ Jesus. All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work.
Beliefs matter.