"For the time will come when they will not endure sound doctrine,…"

This is a good warning. 

2 Timothy 4:3-4(NKJV)

For the time will come when they will not endure sound doctrine, but according to their own desires, because they have itching ears, they will heap up for themselves teachers; 

and they will turn their ears away from the truth, and be turned aside to fables. 

The best way to keep this from happening is to always check what you are being taught against Scripture.  There are a lot of things that "sound" Scriptural but really aren't. 

It takes work.  That is why being in the Word daily your whole life is so important.  As you read the Bible over again and again and again you have to look things up less and less.  At this point I have lost count of how many times I have read the Bible all the way through.  But I keep doing it because each time more and more of it sinks in. 

Here is another technique I find helpful in making sure I am not led astray.  When I am offered proof from Scripture about what someone is saying, I read it.  But I don't stop there.  I also look for other Scriptural references on the subject on my own. 

Why do I do that?  Because it is really easy to cherry pick Scripture to back up a point, especially if the Scripture is taken out of context.  As I have said many times, the Bible is a book of balance and must be taken in its entirety.  If you can find additional Scriptures that back up the view you are being taught then you are probably OK going with it.  On the other hand if you find that almost all other Scripture contradicts the one Scripture used to justify a view….beware.  It may be leading you astray.  Make sense?