I was at a Bible study on Saturday, and one of the readings was one of many confrontations that Jesus had with the Pharisees.
Keep in mind that these boys had memorized the Scriptures to an extent that many of us never will, but Jesus had something unpleasant, even insulting, to say to them -- essentially, "You don't know God."
And that should be sobering. I've studied a lot of theology over the years -- coming from a Reformed background, I really didn't have much choice -- but realize that "theology" can take you only so far. People have to experience God for themselves, and we need to remember that He wants to be known.
An illustration: Some years ago a close female friend and I attended a New Year's Eve party, and we ended up playing one of those "Mars and Venus"-type games. When it came to the questions, she got every single one right about me and I got every single one right about her. Yes, we apparently knew each other that well.
And it's not by mere "study" or even participation in religious exercises or church activity but also a day-to-day life with God that demonstrates whether someone knows Him. Of course obedience is paramount, but with the wrong attitude it doesn't matter.
My friend gave me a book "Finding the Groove: Composing a Jazz-Shaped Faith" that made reference to the classic John Coltrane album "A Love Supreme." I didn't know until reading that book that Coltrane was referring to God -- in 1957 he had had a four-day encounter during which he heard the "sound of God" and that caused him to abandon drugs.
The author, Robert Gelinas, said that Coltrane never became a Christian as we understand that. Problem? Perhaps. But he understood that mere "religion" won't cut it; he had to find God for himself.
I think that's why Jesus was so well-received by the religious non-elite of His day; He related to people and didn't preach at them (although he did talk about sin). They felt that they were in the very presence of God, and He wasn't threatening, but the Pharisees missed that. And Him.