I believe: An introduction into the Orthodox Faith
V. Rev. Michael A. Meerson
All Christians believe (or at least suppose to believe) in one God the Holy Trinity: Father, Son and Holy Spirit, and the incarnation of the Second Person of the Trinity in Jesus Christ, both God and Man. But for the Orthodox Church this belief is the foundation and unquestionable meaning of its very existence, the Trinity constituting the heart of its liturgy and the model for its structure.