I know I interpret Scripture through my own theological glasses. It is something I need to keep in mind as I study. However, some go so far as to say we can never really know what the Bible says because it says something different to everyone who reads it. But I disagree with these proponents of the so-called radical hermeneutic (an interpretive approach grounded in postmodernism called 'deconstruction'*); who hold we should only talk about the 'core Gospel', and never doctrine, alleging knowledge of objective truth is impossible when reading the Bible. This is utter nonsense! Would God give us a book that was not meant to be understood? And what a sure way of keeping us all 'babes' in Christ who are "tossed here and there by waves and carried about by every wind of doctrine."
...like newborn babies, long for the pure milk of the word, so that by it you may grow in respect to salvation (1 Pet 2:2).
For everyone who partakes only of milk is not accustomed to the word of righteousness, for he is an infant. But solid food is for the mature, who because of practice have their senses trained to discern good and evil (Heb 5:13-14).
And He gave some as apostles, and some as prophets, and some as evangelists, and some as pastors and teachers, for the equipping of the saints for the work of service, to the building up of the body of Christ; until we all attain to the unity of the faith, and of the knowledge of the Son of God, to a mature man, to the measure of the stature which belongs to the fullness of Christ. As a result, we are no longer to be children, tossed here and there by waves and carried about by every wind of doctrine, by the trickery of men, by craftiness in deceitful scheming; but speaking the truth in love, we are to grow up in all aspects into Him who is the head, even Christ, from whom the whole body, being fitted and held together by what every joint supplies, according to the proper working of each individual part, causes the growth of the body for the building up of itself in love (Eph 4:11-16).
Yes, there may be differences of opinion about what the Bible says, differences that can sometimes be resolved with humble interaction and much time; but among Christians I believe there is never an excuse for avoiding what the Bible has to say, on the false grounds that knowledge of the truth is impossible.
In fact, I believe that John 7:17,
If anyone is willing to do His will, he will know of the teaching, whether it is of God or whether I speak from Myself.
tells me how certainty (spiritual discernment and assurance) may be arrived at when studying Scripture. Basically, when my heart is right, God will give me the capacity to understand His truth. In other words, if my motive is to know God's will, I believe I will be given assurance from the Holy Spirit that the teaching of Scripture is true, which will be much more convincing than all the logical arguments in the world.
As I study Scripture, these are the interpretive guidelines I adhere to:
First of all, because I firmly believe I should stand by the important hermentical law that the Bible should be interpreted literally, I seek to understand the Bible in its normal/plain meaning. In other words, I look for the intended meaning of Scripture and stay away from allegorizing and symbolizing Bible verses and passages that should be understood literally.
Secondly, I seek to interpret each verse/passage historically and contextually. (Historical interpretation is understanding the culture, background, and situation in which the text was written. And contextual interpretation is always taking the surrounding context of a verse/passage/book into consideration when trying to determine its meaning.)
Lastly, I prayerfully consider all possible interpretations, comparing them against what Scripture says---even the ones that are not the traditional or popular interpretations of today. (I remember Martin Luther...)
*Rejecting "modern" epistemology [the study of knowledge and justified belief] with its insistence on foundations and proper method, postmodernists, sometimes on highly sophisticated grounds, argue that there are no secure foundations, and all methods are themselves theory-laden. The result is that there is no univocal, authoritative "meaning" in the text itself. If one must use the word "meaning" of a text, one should speak of the "meanings" of the text---that is, the different meanings that different individuals or different interpretive communities will find there. Indeed, properly speaking the meanings are not really in the text itself but in the interpreters of the text, as they interact with it. - D.A. Carson, Exegetical Fallacies (Grand Rapids: Baker Books, a division of Baker Book House Company, 1998)