Come out from among them

2 Corinthians 6:17 Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you,

For an example of what it means to separate from the world, take a lesson from the world itself.

Do the people of the world concern themselves in matters of understanding right Biblical doctrine?

For the most part no, they do not. In fact, they typically get far away from the Bible's spiritual things.

We, the elect children of God, do that in reverse.