" It is a simple test, but an immediate one: for the doctrine of the Trinity, of the Incarnation, of human sin and our need for redemption, the victory of the cross and the grace of the resurrection, forgiveness and repentance, love and deification, the intercession of the saints and especially of the Mother of God – all these are present in the prayers we offer in the liturgy, present not just as doctrines but as truths that express the mystery in which we participate through the prayer of the Church, with the divine liturgy at its heart. "

― Andrew Louth , Introducing Eastern Orthodox Theology