Why does Paul tell believers to come out and be separate from the world?
Scripture says to come out and be separate because the world is diabolically opposed to everything believers believe. This is not a retreat into monasteries; rather, God calls His people to separate from what is totally different from their beliefs, promising to receive them and be a Father to them.
Les explains that the conclusion follows from the arguments already given: believers are to come out of a world that is diabolically opposed to everything they believe. He clarifies that this does not mean retreating into monasteries as was done from A.D. 500 to 1500, the Dark Ages, when the Word of God was confined to the monasteries and the average man had no access to it. When the Word of God is withdrawn, the human race goes down, and Israel also went down nationally when she lost contact with the Word. So the call is to come out from those totally different from our beliefs, be separate, saith the Lord, touch not the unclean, and God will receive them and be a Father to them. Les then points to Genesis chapter 12, where Abram is told to get out of his country, from his kindred, and from his father's house.