If we want to know what the Bible says about an issue, what methods can help us to find all the relevant scriptures? If we want to know what the Bible says about an issue, what methods can help us to find all the relevant scriptures? Particularly if someone is looking for a "clear, unambiguous, direct statement in Scripture" (source). A sola scriptura perspective is sought.
The following tools are good for determining what the bible says about a matter.  Take, for example, this question about pets going to heaven.  If you wanted to know the answer, you should consult:
1. A Concordance
The first tool that just about any pastor is going to use to answer a question such as this is a concordance. A concordance is nothing more than an index of words in Scripture, arranged in dictionary form.  The best concordance, of course, is the one in our heads.  The next best one is one in a book.
The classic work here is Strong's Concordance, which originally indexed the KJV bible. Other editions look at the Greek and Hebrew words underneath, or use other tricks to better index the words. Using google, by the way, is another easy way to find verses you sort of know, but don't know where they are.
Searching for 'pets' you will find nothing.  Searching for 'dogs,' you will find that it is usually an insult to a person, not anything about the animal. (Clearly, the writers misguided cat-o-philes, I suppose. ) Regardless, the point is that if you look up any of the words you might think are useful, you just won't find anything.
One word of warning: It is tempting to think a concordance can answer everything. It can't. And, references always need to be read in context.  But, it is a good place to start.
2. A Topical Dictionary of the Bible
Sometimes, a word might not appear in Scripture, but an idea does.  The word 'Trinity' for example, appears nowhere in Scripture - BUT the idea certainly permeates the whole.  For concepts, a topical dictionary like Nave's or one of these are useful.
In these dictionaries, key words will be explored, and centuries of Christian knowledge will be summarized, as a useful starting point for where you are heading.  Again, you need to read what they write in context, but it will show you where to focus your study.
Nave's lists Pestilence (hey some people keep spiders as pets!), Peter, and Pethiah - so, yeah, maybe not.
3. A Systematic Theology
Finally, for larger topics, one should consult a systematic theology.  Several (if not most!) theologians will write books that seek to put a propositional order to everything in Scripture.  Typically, this means they will start with questions like &quot;The Nature of God,&quot; &quot;The Nature of Man,&quot; &quot;The Nature of the Bible,&quot; etc...  If you know what transubstation or predestination ante praevisa merita is, you jump straight there and learn a lot - but more likely, you need to be exposed to the terms and directed as to why these things are important.  That's what a systematic theology would do for you.
In this case, looking at the nature of the soul, the curse of the law, and the need for redemption only when there is transgression, one could begin to formulate questions around whether or not animals have souls, whether or not the &quot;image of God&quot; is a necessity for heaven, and the like.  But that takes work!
And, that ultimately, is where all of the tools need to be placed in perspective. Each of these tools is a map to a microscope.  If you don't have an overall picture, these tools won't provide a lot of light. But, with regular reading, the overall map takes shape and you will be able to find these answers.