As Christians, how we treat other people speaks louder to the world regarding the authenticity and validity of our beliefs than the doctrines we teach, the creeds we confess, or even the moral and good lives we try to live. If we are self-serving, self-promoting, unforgiving, and arrogant in our relationships, that will drown out what we have to say. When we hold grudges against fellow Christians, cling to pride, and refuse to forgive each other, we may affirm the skeptic’s suspicion that Christianity is a facade of moralism with no real supernatural power to change people’s hearts.
On the other hand, if we are genuinely overwhelmed with the grace and forgiveness that God has shown to us in Christ, and if the love of God is overflowing out of our hearts and manifesting itself in our relationships, then we are witnesses to something that is foreign to the world and its legalistic approach to God. We are living testimonies of the supernatural power of God to break the power of selfishness and sin and establish a new life in the Spirit (Rom. 7:6). To one degree or another, the unbeliever lives by the flesh and seeks to gratify himself while denying God the glory He is due. Nobody is surprised when they encounter this self-orientation in others as it is the natural condition of all people. The world, therefore, does not understand Christian love and forgiveness that is not self-serving. When a Christian loves and forgives liberally, especially at some cost to their property or reputation or health, the unbeliever sees something radically different than what he is familiar with in the world.
Jesus said if we only love those who love us, we are in accord with the way the world operates, and there is no benefit for us (Luke 6:32). Jesus said we are to love people who hate us and wrong us. We are to pray for them and meet their needs and endure their scorn. The apostle Paul exhorts us to bear “with one another and, if one has a complaint against another, forgiving each other; as the Lord has forgiven you, so you also must forgive” (Col. 3:12–13). These things are impossible apart from God, and so when they are present in our lives, the unbelieving world sees something unfamiliar to them, something divine, and something they know they need. They see the Spirit of Jesus Christ at work in us.