Service is also a response to God. Jesus taught many times over that we should love our neighbor which means to do good for our neighbor. All should use the gifts God has given them to serve God by serving others. Teaching is the next response to God. Teaching also involves sharing life experiences coupled with Biblical guidelines to help each other in relationships with each other.
Fellowship is the final response in the bulls-eye picture.
The church is a fellowship, not an organization. It exists only as the result of God's saving work and man's faith in that work. Those who have accepted the Lordship of Jesus must relate to each other in positive ways that promotes God's love to the community and to the world. So God must be the center of our fellowship with one another.