Occasionally when working with a group, I have put to them a question something like this: If someone, thinking of you as a Christian, would ask, What is Christianity? What is the essence of it? what would your answer be? Responses typically take two directions. One points to Christianity as having to do with living a loving and Christ-like life. The other points toward believing in Jesus Christ as one's Savior and Lord.
I have devoted much of my life to Christian peace witness, and this question of what really is the heart of Christianity presents itself continually in such work. In the peace and justice movement, the living out of nonviolence and peacemaking and the struggle for justice are widely seen as the heart, the essence.
If we look to the New Testament as foundational for our understanding of Christianity, two aspects stand out: what God has done for us, and what God asks of us. God in Christ gave his all for us, and we are expected to give our all (something incomparably less) to God in response.
In the Christian understanding grounded in the New Testament, everything depends on God's initiative: "For God so loved the world that he gave his only Son" (John 3:16a); "in Christ God was reconciling the world to himself" (2 Corinthians 5:19a); "In this is love, not that we loved God but that he loved us and sent his Son to be the atoning sacrifice for our sins" (1 John 4:10). The expressive, reaching-out part of God entered into our human condition and lived as a human being in our midst; "the Word became flesh and lived among us...full of grace and truth" (John 1:14).