Christianity is a group thing. Jesus not only preached, taught, and healed, he gathered a group of people who became his disciples. Perhaps Jesus knew that a message so bold as the one he preached, a way so tough as the one he set forth, a vision so radical as the one he shared could not be sustained alone. We need the support of our fellow Christians.
"Christianity is essentially a social religion," said John Wesley, founder of Methodism. "To turn it into a solitary thing is to destroy it." This faith cannot be practiced in a home correspondence course, by sitting quietly and watching someone else be religious on TV, or by thinking your own private thoughts in the woods.
You need others, the world being what it is and the demands of the faith being what they are. You need others to support you in times of crisis, defeat, loneliness, fear, or frustration. Everyone needs somebody, sometime, especially anyone who tries to live out the gospel in his or her daily life.
You need others to prod, challenge, and question you when you get comfortable, smug, and complacent about your faith. Nobody gets so smart, so together, so dedicated that he or she becomes exempt from the need to grow in faith.
So God gave us the church. I say "gave us the church" because, according to the New Testament, the church was there from the start, the natural response to a Savior who saved people by bringing them together. The church is a gathering of strange people, people like you and me, people who have no other earthly reason to be together other than they have heard God call their name and intend to follow him.
William H. Willimon, The Way: Confirmation for Discipleship in the United Methodist Church, (1981), p. 11.