A simple answer would be the Nicene Creed.
But here is an excerpt from my book, FWIW:WHAT is the EMPHASIS of the GOSPEL?
Some say, “Christ has paid my sin debt, and therefore I am no longer guilty.” Then, they continue to live an unaltered, unmoved life, thinking that heaven awaits them when they die. Others say, “I must strive to know God through a life of contemplation and asceticism.” But at the end of their life they still do not know Him.
So, what is the proper emphasis of the Gospel? Is it forensic in essence, or mystical? Is the theme of the Gospel soteriological
, i.e. the salvation of man, or is it doxological
, i.e. the glory of God? Is the Gospel to be understood as God’s gracious condescension to fallen man, or fallen man’s inability to know a transcendent God?
The Catholicism and Protestantism of the West have attempted to answer these questions via the rationalistic approaches of Scholasticism and various “systematic theologies.” Learned and sincere theologians have endeavored to reduce the deep mysteries of God and the rich treasures of the Holy Gospel to a system of mortal logic that will make them comprehensible to the finite mind. But God cannot be known by any system of mortal philosophy; and the beautiful truths of the Gospel cannot be adequately encapsulated in a logical syllogism.
Therefore, Orthodoxy simply affirms what the Scriptures say, and does not stumble over apparent contradiction or paradox. The truths and reality of God transcend contradiction and paradox, and thus we prostrate our own fallible understanding before His holy Mysteries. We accept that God is unknowable, and yet by grace we experience Him. We affirm that Christ has paid our sin debt, and yet we recognize that the meaning of the Cross is too vast to be summed up by the analogies of mortal jurisprudence. As Orthodox Christians, we proclaim the Nicene Creed as the summation of the Gospel, knowing that mystical depth is found in its brevity and concision. Our Creed is not a comprehensive dissection of divine truth, but a sufficient description.
The Holy Gospel is the mystical message of redemption, grace, mercy, judgment, hope, sacrifice, salvation, peace, love, atonement, forgiveness, reconciliation, oneness, repentance, justice, deliverance, life, heaven and hell. This holy message has been entrusted to the Church, which proclaims its truth to the world and reveals its Mysteries to the faithful. We adore the Holy Gospel as the light for our souls, but we dare not claim to grasp its depth with our finite minds. We immerse ourselves in the ocean of the Divine, allowing the Spirit of His waves to draw us to His knowledge and nearness.http://bookstore.authorhouse.com/Products/SKU-000365534/MYSTERY-and-MEANING.aspx