In our times we hear many various answers such as: “To be a Christian means to recognize Christ’s teaching, to try to fulfill His commandments.”This, of course, is the best of such answers. The first Christians, however, answered the question in a completely different way. From the very first pages of its history, Christianity appears before us in the form of a harmonious and unanimous community. Outside of this community there were no Christians. To come to believe in Christ, to become a Christian – this meant uniting with the Church. This is repeatedly expressed in the book of the Acts of the Apostles, where we read that the Lord daily added the saved to the Church (cf. Acts 2:47; 5:13-14). Each new believer was like a branch grafted to the tree of Church life.(Christianity or the Church?)
H/T Fr. Josiah Trenham http://frjosiah.wordpress.com/2011/08/11/christian-life-is-impossible-outside-the-church/
The entire work in PDF format:
http://www.holytrinity.oh.goarch.org/assets/files/Documents/CHRISTIANITY%20OR%20THE%20CHURCH.pdf