The truth is not a matter of opinion.
, at least, for all I know, if a man look to the Lord God Jesus Christ, who is the "Truth", and thus the Light, and shun evils as sins against Him, it is the beginning,
So, this right here is the reason I asked the question. You claimed that "the point is not whether the interpretation suits one's doctrine, but whether the interpretation is true." Yet when asked how such truth is to be determined, you immediately appeal to inward disposition, personal orientation, and doctrinal assumptions framed in the language of personal opinion.
That does not provide an objective standard by which interpretations may be tested. It merely describes the state of the interpreter.
(To be clear, your appeal to Jesus as the Truth is quite correct. That is indeed, as you say, the beginning. The issue is the subjective way in which you couch that truth.)
...but there is also a need to have the loyalty to the truth itself to be higher than the position of the church of one's birth or family, tradition, etc. For otherwise, would not a mean merely try to argue in favor of his own tradition, not being interested what is the actual truth?
Now we're getting somewhere!
The fact is that your use of the word "also" here is where you go wrong. Loyalty to the truth is not something we have along side our personal opinions or church or tradition. It is THE supreme thing. Truth is the object of one's loyalty - to the exclusion of all others.
Very rarely he can be given, I think, more immediate light from the Word to see what is the true, but more realistically, most people, apart from the explanation by other men, can hard see the truth immediately in such light. However, if they are interested in the truth, being in the affection for the truth itself and good, then they can see in the writings of other men, whether their explanation of the Word is more sound, rational, correct.
What a man can or cannot see is not the standard. There is simply no such thing as an irrational truth. Whether one detects the errors within a stated claim or not is not relevant to whether such errors exists. What's more, the degree to which one's loyalties are to anything other than the truth itself is the degree to which they are blinded to anything that contradicts the object of that misplaced loyalty. Such loyalties serve to distort one's view of reality, which is the standard. Truth is determined by conformity to reality, not by the intensity of one's convictions concerning it.
So, in continuance of that line of thought, allow me to answer the question I asked you. How are we to determine which interpretation of scripture is true?
Truth, any sort of truth, whether biblical, theological, philosophical, scientific or whatever, is determined by conformity to reality. A thing is true because it corresponds to what is, not because it is ancient, traditional, emotionally satisfying, spiritually appealing, or intensely believed.
For that reason, the highest loyalty of a rational man cannot be to church, tradition, teachers, institutions, experiences, inward impressions, or even his own prior conclusions. His highest loyalty must be to the truth itself, wherever it leads and whatever it overturns.
That is what it means to be intellectual honest. To be loyal to truth is to permit reality to correct you. It is to follow reason, evidence, context, and logical consistency even when they conflict with your preferences, your assumptions, your tradition, or your theological system. A man who is truly loyal to truth does not ask, "What interpretation preserves my system?" He asks, "What interpretation is actually warranted by the text, the context, the grammar, and reality itself?"
Truth remains what it is regardless of whether we perceive it correctly. Our task is therefore not to create truth, nor spiritually intuit it into existence, but to conform our thinking to what is objectively real.
How then do we conform our thinking to what is objectively real?
By the honest use of reason.
Reason is the faculty by which the mind recognizes coherence, contradiction, implication, context, and meaning. It is the means by which we compare our beliefs to reality itself.
For that reason, loyalty to truth necessarily requires loyalty to rational consistency. A contradiction cannot become true through sincerity, tradition, spiritual sentiment, institutional authority, or intensity of conviction. Truth must be coherent because reality itself is coherent.
This is why rationality is not the enemy of truth, but one of its necessary preconditions. If reason is abandoned, then there remains no objective mechanism by which truth can be distinguished from imagination, preference, or doctrinal invention.
A man conforms himself to reality by continually permitting his assumptions, interpretations, doctrines, and conclusions to be tested by reason, evidence, context, and logical consistency, correcting them wherever they fail to correspond with what is objectively true.
One final point, in case you may be thinking that such a position is somehow unpious or that it places one's own mind in authority over scripture or indeed over God himself. I can assure you that nothing could be further from the truth.
Reason is not a standard external to God by which He is judged. Reason is rooted in the nature of God Himself. God is not irrational, contradictory, or incoherent. Scripture presents Him not as the enemy of reason, but as its eternal source.
This is profoundly reflected in John 1, where Christ is identified as the Logos. The term does not merely refer to a spoken word, but to reason, rationality, meaning, coherence, and intelligibility itself. Christ is presented as the eternal rational principle through whom all things were made and by whom reality is rendered intelligible.
For that reason, rational coherence is not something standing above God. It is an expression of His very nature.
This is why contradictions cannot become true through appeals to mystery, tradition, authority, or spiritual sentiment. A thing cannot both be and not be in the same sense and at the same time. Irrationality is not a divine attribute. The honest use of reason is therefore not an act of rebellion against God, but an act of submission to the God who is Truth itself.
To abandon reason is not humility. It is the surrender of the very faculty by which truth, meaning, coherence, and even the words of Scripture themselves are understood.