First, we need to define "friendship evangelism" to establish a baseline for answering the question. Friendship evangelism is also known as lifestyle evangelism and relational evangelism. The basic thought underlying friendship evangelism is to establish a friendship with an unsaved person in order to one day share the gospel with him/her. People have differing views on what friendship evangelism is. Here are three common views:
Should Christians engage in 'friendship evangelism'?
1. The Christian establishes a relationship before addressing the unsaved person's need for a Savior.
2. The Christian lives a solid, righteous life—a living testimony—before others so that they desire that kind of life and ask how to achieve it. When the question is asked, the gospel is shared.
3. The Christian lives a righteous life in the world, not saying anything or planning to say anything directly about the gospel.
The basis for friendship evangelism is in the Sermon on the Mount, where Jesus said (Matthew 5:14–16), "You are the light of the world. A city set on a hill cannot be hidden. Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven."
So while friendship evangelism is based on Scripture, it is not overtly scriptural in all aspects. James 4:4 says, "Do you not know that friendship with the world is enmity with God? Therefore whoever wishes to be a friend of the world makes himself an enemy of God." Second Corinthians 6:14 says, "Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness?" Both of these passages state that establishing a close friendship relationship with an unbeliever is wrong. Now these passages do not say that being friendly toward an unbeliever is wrong. As a matter of fact, we are commanded to love all, which includes believers and unbelievers alike. In the Upper Room Discourse, Jesus commanded His disciples to love as He had loved them (John 15:12), and He loved us enough to die for us before we loved Him (Romans 5:8). But loving unbelievers and establishing an intimate friendship relationship with them are two different things.
Another problem for Christians with friendship evangelism is that we have been commanded by Jesus to "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you" (Matthew 28:19–20). One cannot follow this command and yet silently wait for an opportunity to share the gospel or for someone to ask about it. Romans 10:14 says "How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching?" Later, in Romans 10:17, we are told that "faith comes from hearing, and hearing through the word of Christ." Faith doesn't come by all Christians behaving well, but by Christians speaking the gospel.
Friendship evangelism observes one command of Jesus, but it ignores another. We are to live a godly life, but we are also to tell others. Christians should do both: be a light in the world, and point people (actively, not passively) to Jesus. A Christian should not limit himself/herself to passively living a good life.
What is the key to evangelizing friends and family without offending them?
How can I share my faith in the workplace? Why should I talk about my faith at work?
How can I be an effective witness for Christ? How can I effectively witness to a lost world?
What are some tips for how I can share my Christian testimony?
Should Christians have close friendships with unbelievers?
Truth about the Christian Life