II Corinthians 5:20,21
“Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ’s stead, be ye reconciled to God. For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.”
First and foremost we are Christ’s ambassadors; we are the extension of Heaven here on earth. To do what? God leaves us here to share the good news with the lost world around us. If Christians don’t do it, who will?
Secondarily but just as important is that each of us as individuals and as members of the body of Christ, being indwelt with the Holy Spirit are the only restraining force holding back the flood gates of evil. As Paul makes so clear in 2 Thessalonians 2:7 that the Church is a dam in the world’s river of iniquity.
For the mystery of lawlessness is already at work; only He (the body of Christ) who now restrains will do so until He (the body of Christ) is taken out of the way.
II Thessalonians 2:7
One day He is going to call us out (1 Corinthians 15:51,52; 1 Thessalonians 4:13-18), and that river of wickedness will flow over this planet like it never has before. But until that happens, we are to share the gospel and be that dam in the river of evil.
And have no fellowship with the unfruitful works of darkness, but rather expose them. For it is shameful even to speak of those things which are done by them in secret. But all things that are exposed are made manifest by the light, for whatever makes manifest is light.