When you hear the word "evangelism" what enters your mind? You probably think of sharing the good news of Christ's life, death and resurrection, with an unbelieving person (or people) in hopes of another person would be converted and saved by God's grace.
And while I long for this as much as any Christian, I wonder if that understanding of evangelism is too limited. In Romans 1:15 Paul writes, "I am eager to preach the gospel to you also who are in Rome." The Greek word translated "preach the gospel" is the word euangelizo, which most literally means, "to evangelize." So Paul writes that he is eager to evangelize those who were in Rome.
Nothing extraordinary about that, right? But who exactly is Paul so eager to evangelize? He says, "you also who are in Rome." And he's already told us a good bit about these people: they are loved by God, and have been called to be saints (v.7). They are those whom Paul thanks God for, because their faith is being proclaimed in all the world (v.8). They are those whom Paul is eager to visit so that he might be encouraged by their faith (v.11-12). They are his "brothers" (v.13).
In other words, Paul is eager to evangelize these Christians. The evangel -- the gospel -- is not merely the news people need to be converted and brought to faith. It's also the very same news that Christians need to grow up in faith and be strengthened day by day after their conversion.
So let's be zealous about evangelism, Christians. Only, let's not limit our evangelism to non-believers. You and I need the gospel every bit as much as they do.