So I tell you this, and insist on it in the Lord, that you must no longer live as the Gentiles do, in the futility of their thinking. They are darkened in their understanding and separated from the life of God because of the ignorance that is in them due to the hardening of their hearts. Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, and they are full of greed.

Ephesians 4:17 – 19

We are a new community of faith in Jesus Christ, from a variety of cultures.  We need to live like that because that is our new identity, an eternal one.  The enemy of our souls tries to pull us back into the world that we were delivered from by the new birth and sanctification.

Paul gets a bit stern here, you must no longer live as the Gentiles do, in the futility of their thinking.  As we noted earlier, in Ephesus believers were from both Greek cultures and Jewish cultures who lived together as the redeemed Body of Christ.  Paul was well aware of the fact that the Gentile believers were tempted to return to their old way of thinking.  Paul described this as being darkened in their understanding and separated from the life of God because of the ignorance that is in them due to the hardening of their hearts.  That is, before the came to know and accept Jesus Christ.

Paul is speaking as a Jewish follower of Christ, steeped in ancient Jewish insistence on separation from the world.   He describes the “unsaved” Greeks as having lost all sensitivity.  Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, and they are full of greed.  Ignorant, insensitive, impure, full of greed – a fit description of a culture without the Gospel of Jesus Christ.

I personally see no difference between the situation in Ephesus and our own times.  Hard, unbelieving hearts lose all sensitivity and then the doors are open to all evil.  We need to be aware of this at all times.