This is the question CMS seeks to answer in its new short film celebrating its 214th birthday on Friday.
The mission was founded in 1799 by, amongst others, John Newton who penned the classic hymn Amazing Grace.
Newton was present at the meeting at the Castle and Falcon Inn in the City of London that brought CMS into being on Friday 12 April 1799.
A new version of the hymn is performed by Jon Bilbrough and appears as the soundtrack to the film.
Philip Mounstephen, CMS executive director, said, "CMS exists for the world to know Jesus in a way that changes the whole of life. All we do is aimed at raising up people in mission for that purpose.
"Today we are a vibrant mission community of supporters, members, mission partners and many others who make that possible.
"I hope this film will inspire many more to join us."
Joseph Steinberg, CMS director of mission stewardship filmed the video with Ian Oakley of Whitestone Media.
The video shows different places around the world where CMS is operating and how people and communities are being positively impacted.
One project they visit is the Neema Crafts Centre, which came into being in 1999 in the region of Iringa, in Tanzania. The centre provides training in crafts and much-needed employment opportunities for people with disabilities.
It is founded on the principle that God has a purpose for everyone. "You are not defined by your disability, you are defined by your ability," says Katy Ray, a CMS mission partner at Neema Centre.
In Chaco, northern Argentina, CMS has been translating and spreading the Bible among Amerindians.
The film also shows a CMS team operating in Hull, one of the top 5% most deprived areas of the UK, where children and their families are being provided with a proper breakfast before school.
Jesus here "brings hope that is long-lost", says one CMS partner.
The final stop is a Nepali jail, where most of the inmates are from a Hindu background. Yet 22 prisoners were baptised in one year. Some are now leaders in the worship fellowship and group prayer.
"Mission may look very different now but CMS people are still making incredible sacrifices to share Jesus and see lives changed," says Steinberg.
"I was moved to tears on this trip, as I witnessed the difference CMS people make to people's whole lives."
Watch the film here: