What happens when people who claim the name "Christian" try to find biblical backing for their own opinions? Luther weighed in on this in 1526, in his writing Against the Fanatics:
"This is what all factious spirits do: they first concoct an opinion. If it pleases them, they then attempt to force the Scriptures to agree with it. But whoever derives the right faith from the words will believe like this: ... God grant that as long as I have the words, I will not seek to speculate any further; what he says, I will keep. Thus the believer envelops himself in the Word, will not let himself be turned aside from it, and is also thereby sustained."
So today, we see all kinds of ways in which people begin with their own opinions and then go looking for Scripture to back them up. And they will in most cases find some way to use the Bible to back up their opinion. But the wise person will start with Scripture, and grow to understand its message more and more, and thus build understanding and insight that comes from Scripture, not from human understanding. Luther pegs the truth when he says that if we do not let ourselves be turned aside from the Word, we will be "thereby sustained."