Simply by being a member of the church of Jesus Christ each Christian has a responsibility to be involved in the missionary call of the whole church. We should all be praying, all giving, all sending.
There are two particular passages in which the apostles call all believers to be involved in the work of evangelism. First a passage from Paul (Colossians 4:5-6), and then one from Peter (1 Peter 3:15-16).
The words of the Lord through His apostles are clear. Evangelism is not simply the task of church leaders, pastors, and evangelists who are specially called and gifted. (Though the New Testament does recognize the particular responsibility of leaders and pastors in this task and teaches us that God does indeed gift some for this work with special abilities; see, for example, Ephesians 4:7-12 and 2 Timothy 4:1-5.) But it is not only the teachers and evangelists who have this task set before them; rather, every believer is called to be ready “to give the reason for the hope that you have” and to “make the most of every opportunity.”
This is how we are to think about our own lives. We are always on trial for Christ; our faith is always on trial. In our homes before our children and spouses; in our schools and colleges before our teachers, students, friends, and classmates; in our workplaces before our colleagues, bosses, employees, and customers; when we are playing or relaxing; whatever we are engaged in, wherever we find ourselves, we are put there by God for “the defense of the gospel (Philippians 1:7).”
As Francis Schaeffer used to say often: “We live before a watching world.” It is incumbent, then, on us to remember that our behavior, our words, our manner of speech, and our attitudes of heart are always being judged by non-Christians. Unbelievers are drawing conclusions about Christ and about the truth of Christianity from everything we say and do.
Excerpt adapted from The Heart of Evangelism by Jerram Barrs.