In the 217 years of Church Mission Society's existence perhaps one of the most radical steps we have taken was to drop three small letters from our name. In 1995 the Church Missionary Society became the Church Mission Society.

"What's in a name?" asked Shakespeare. In this case the answer is, "Quite a lot." To move from 'missionary' to 'mission' was to move from a word that conjured up images of pith helmets and 'doing good to the natives' to something much more contemporary. After all, every business going has its own 'mission statement'.

But perhaps we've replaced one problem with another. Mission was once a fairly specifically Christian word. Now its usage has become general. Has it become so general as to be useless? Should we ditch it as not distinctive enough?

It's striking that one of the Archbishop of Canterbury's stated priorities is 'evangelism and witness.' The absence of the 'M' word is not coincidental. And there have certainly been problems with its usage. It was not uncommon once upon a time (but much less so now) to hear bishops say, "Well of course everything we do is mission," which generally meant that nothing they did was mission.

So has the word passed its sell-by date? Should we replace it with something else? And is it time to follow the Archbishop's lead and rehabilitate evangelism?

There's been much ink shed in the attempt to define the relationship between mission and evangelism. One of my predecessors as leader of Church Mission Society, John V Taylor, talked of a "three-stranded presentation of the gospel". That is to say Christians are to "articulate the gospel through what they 'say' (proclamation), through what they 'are' (witness) and through what they 'do' (service)" (For all the World).

However, John Stott was uneasy with that on the grounds that it made service "a sub-division of evangelism" rather of value in its own right. From a very different theological perspective Ken Leech railed against what he called 'implicationism', the suggestion that a concern for justice was an 'implication' of the gospel. For him it was the gospel; it is mission.

I want to be radical and suggest that actually mission and evangelism are the same thing, because they have the same thing – the same person – at their heart.

The biggest trend in our understanding of mission in recent years has been the realisation that mission is God's business. Mission is missio Dei: the mission of God. But there is a danger in so emphasising missio Dei that we assume that the mission of God is a rather nebulous concept. It expresses a general, vague, divine goodwill towards the whole world. The mission of God is in fact sharply focused, focused specifically on his Son, Jesus Christ. Indeed, God has no mission apart from Jesus. Everything of significance he has done, in creation and in redemption, he has done in, and through, Jesus.

God has no mission apart from Jesus. And that means that the mission of the Church must be sharply focused on Jesus to, and in particular on the simple but profound proclamation that 'Jesus is Lord'. In saying that we proclaim that he has no rivals and everything in heaven and on earth must be brought under his just, gentle and generous rule.

And as for mission so for evangelism: it is Jesus that is at its heart. What is the 'evangel'? The gospel writers used it in a subversive sense. When Caesar Augustus took the throne he proclaimed the 'evangel': that through him alone people could be saved. But that claim was subverted by the Christian faith. So when the gospel writers proclaimed 'the good news of Jesus Christ' they were announcing regime change, and that Jesus, not Caesar, was Lord, and that his lordship extended over every area of life.

So it does. And the task of mission and evangelism today is identical, because it is all about the proclamation and the manifestation of Jesus' lordship over all, from the micro-detail of the human heart to the macro-sweep of the whole created order. Which is why today you'll find CMS people in mission working in a wide range of areas: from Kailean and Kim Khongsai working in creation care in London, to Ram Prasad Shrestha training new church leaders for Asia and providing earthquake recovery in Nepal, to Doug and Jacqui Marshall giving practical and spiritual support for asylum seekers in Malta. Each of them putting their mission call into action and announcing in word and deed the lordship of Jesus over every area of life.

That is the calling of the Church of God; that is our mission; that is our good news. And that, above all, is what the Lord, Jesus Christ, calls us to: to proclaim that he, and he alone, is Lord.

Rev Canon Philip Mounstephen is executive leader of the Church Mission Society @cmsmission.