Years ago, I was out sharing the gospel and had a younger guy with me who was sharing his faith for the first time. We were talking to a big, burly biker with giant arms and tattoos everywhere. The biker told us, "Get out of here and leave me alone."
I said, "Let's go."
But my friend said, "Okay, fine. We're not going to cast our pearls before swine."
That is not the verse to quote to someone when you're sharing the gospel. That is the verse you may think of, but it isn't the one you quote.
We do have to make an evaluation as Christians. We have to determine who the people are who don't regard the things of God. There's a place for judging. Judgment is the exercise of critical thinking, and judgment is needed on occasion.
John 7:24 tells us, "Do not judge according to appearance, but judge with righteous judgment." The Bible has told us to judge, but we are to judge by what is right. We are not to condemn, and we are not to be judgmental. Rather, we should make evaluations. We should be discerning. We should express our opinions on right and wrong, truth and lies, good and evil. In fact, the Bible tells us, "Do you not know that the saints will judge the world?" (1 Corinthians 6:2).
The opposite extreme of being judgmental is the naïve acceptance of anything. In the Sermon on the Mount Jesus said, "Do not give what is holy to the dogs; nor cast your pearls before swine" (Matthew 7:6). In other words, "Don't take the holy things of God and offer them to someone who has no interest in them whatsoever." We need to make those evaluations. It isn't violating the Scriptures when we do.