In Ephesians 4:17-24 the Apostle Paul contrasts the spiritual condition and lifestyle of the unbeliever (vv. 17-19) with the spiritual condition and lifestyle of the believer (vv. 22-24).
But the difference is not one of mere outward morality. There is an internal spiritual change that has taken place which is responsible for the stark contrast between the believer and the unbeliever.
What is the agent God uses to bring about this change? The Apostle identifies it for us in vv. 20-21 and this the subject of today's message.