Slogans are catchy. Slogans crystallise our thoughts and capture our imaginations. That’s why they’re so useful for selling ideas. “Just Do It” inspires you to get out there and get active, preferably wearing a certain brand of sporting gear. “I’m lovin’ it” inspires you to get in there and feed the tasty fast food into your system so you can experience the sugar rush. Christians use slogans, too. “Jesus is Lord” is Paul’s brilliantly concise summary of the gospel of Jesus Christ. “What would Jesus do?” was a popular 1990s catch-cry designed to inspire people to imitate Christ. Sometimes, Christian slogans use old languages. The old language gives the slogan weight because it connects us with the great figures of former generations. Take, for example, the Latin slogan semper reformanda.[1] It was probably first introduced by seventeenth-century Dutch Reformed preacher Jodocus van Lodenstein. Semper reformanda is often translated “always reforming”, and explained this way: because the church will never be perfect this side of eternity, it always needs to reform itself in each new generation. So semper reformanda is used as a call to remember that the reformation is never over, and to keep up the reformation effort always. The problem with slogans in old languages, however, is that they can be mistranslated, misconstrued and misapplied. Semper reformanda is a prime example. “Always reforming” is, in fact, both a mistranslation and a shortening of the original Latin slogan. The complete phrase is: ecclesia reformata et semper reformanda secundum verbum Dei: “the church reformed and always being reformed in accordance with the word of God.” Certainly, those who first used the slogan believed that the church is always in need of reform. But they didn’t express it as “always reforming”. Why? Firstly, because they didn’t see the church as doing the reforming; they saw it as “being reformed” by God through his Spirit. Secondly, they realised there was a vital principle that must guide all reformation: “the word of God”. If we translate it as “always reforming”, the slogan might be taken to mean that it’s our job to re-form our ministry or our ideas about God for each new generation based on the needs of the hour. But those who first used the slogan were saying the opposite. They were trying to say that the unchanging word of God needs to constantly reform us. And they were thinking particularly about the need to grow in holiness and piety: to bring the daily lives of Christians into line with the truth of the gospel. Understood according to its original intention, this slogan semper reformanda captures many of the important ideas in this passage in Paul’s letter to the Ephesians. Here in Ephesians 4:14–15 Paul is talking about the growth of the “body of Christ” (which earlier in his letter he described as the “church”). He’s giving a key principle for how this growth happens. When we think about principles for church growth today, we often have in mind things like how we must reform our structures or update our language and presentation of the gospel for the needs of the current generation. While we do need to think carefully about these things, they’re not what Paul is talking about here. Paul’s principle for the growth of the body of Christ here is something far more fundamental. It’s not a principle of presentation or organisation or structural reform. Rather, it’s a principle for us, and for our hearts and lives. It’s a principle for what we say to one another, and how we treat one another. This principle involves God’s