The goal of Christian biblical hermeneutics
The goal of hermeneutics is understanding communications.
The purpose of Christian biblical hermeneutics is understanding God’s message(s) in the Christian Scriptures. That is Christians understand the Bible to in some way deliver divine messages. Other people, or Christians when they are reading for other purposes (e.g. with an interest in history) may rightly understand the Bible in other ways, but a Christian interpreting the Bible as Scripture is seeking a message from God.
The nature of the Bible
The Bible is a collection of works of human communication. These works are of varied genres, come from a wide range of locations, and from a broad span of time. The Bible does not claim1 to have been composed or dictated by God or another supernatural being. It does claim to be inspired by God, and so to contain divine messages. The orthodox understanding (at least among Protestants) however, is that these messages are not encoded, but are plainly to be seen.2
This seems to imply that the many and various (and therefore not at all clear, except to the recipients) messages that the Holy Spirit inspires people to hear as they read Scripture are not ‘the message of the Bible. It seems evident to me3 that God does use the Bible as the stimulus for personal messages, rather as the pun on the Hebrew word for ‘almond tree’ was used to inspire Jeremiah with a prophetic message (Jer 1:11-12). My point here is that such personal messages stimulated by Scripture are not messages of Scripture (which would mean they were for all times and all places).
Clarity or perspicuity
If the divine message(s) of Scripture are clear and obvious (perspicuous) then they cannot be thought to reside in the details. For the details of what the Bible says are often far from ‘clear and obvious’. For example, should Christians prefer to worship on Saturdays or on Sundays? Worship on Saturday is enjoined on Israel in the stipulations of the Sinai covenant, worship on Sunday is inferred from several New Testament references but is not unequivocally enjoined. Therefore my conclusion is that neither my (Baptist) practice of gathering with others on Sundays, nor the practice of Adventists (to gather on Saturdays) is either enjoined or forbidden by the Bible’s teaching.
On the other hand, ‘you should not kill’ is one of the Ten Commandments, and this is reinforced by Jesus into a warning against the sort of thoughts (anger and superiority) which might lead to killing (Matt 5:21-22). This goal is reinforced in a number of other places and so seems a clear teaching of Scripture.
But what you are saying is not precise
Some may object that what is suggested above is not precise. How many times does an idea need to be repeated before it becomes ‘clear’? This objection is true, but does not appear fatal. We tolerate a justice system based upon ‘beyond reasonable doubt’. I have served on a jury where the nature of such reasonable doubt was explored (I suspect a significant proportion of all juries spend time on this, since most cases that involve juries deliberating seem to involve some doubt). This system of ‘beyond reasonable doubt’ is oxymoronically not certain, but it is the most fair and equitable we have been able to devise. Life in a fallen world lacks certainty. Muslims and others who claim that the words, and not merely the message(s), of their Scriptures are divine sidestep this uncertainty, for Christians the Bible’s teaching should claim to be a divine word for all only when it is clear and evident – perspicuous.