Before the new testament was the Divine liturgy.

We Orthodox live Christ within the Divine Liturgy, or rather Christ lives within us during the Divine Liturgy. The Divine Liturgy is a work of God. We say: “Time is a creation of the Lord”. Among other things it means now is the time for God to act. Christ liturgises, we live with Christ. The Divine Liturgy is the way we know God and
the way God becomes known to us. Christ celebrated the Divine Liturgy once and this passed into eternity. His divinised human nature came to the Divine Liturgy. 

We know Christ specifically in the Divine Liturgy. The Divine Liturgy we celebrate is the same Divine Liturgy which was done by Christ on Great Thursday in the Mystical Supper.  The 14th through the 16th chapters of the Gospel according to John is one Divine Liturgy. So in the Divine Liturgy we understand Holy Scripture. The early Church lived without a New Testament, but not without the Divine Liturgy.

The first records, the written hymns, exist in the Divine Liturgy. In the Divine Liturgy we live Christ and understand His word. As Christ cleansed His Disciples with his word and said to them: “You are already clean because of the word which I have spoken to you” (John 15:3) and He washed the feet of His Disciples with water, during the Sacred Washing, so also in the first section of the Divine Liturgy He cleanses us that we might attend later His Table of love. The purpose of the Divine Liturgy is to convey Christ to us. 

The Divine Liturgy teaches us an ethos, the ethos of humility. As Christ sacrificed Himself, so also should we sacrifice ourselves. The type of the Divine Liturgy is the type of impoverishment for us. In the Divine Liturgy we try to be humbled, because we have the sense that there is the humble God. Every Divine Liturgy is a Theophany. The Body of Christ appears. Every member of the Church is an icon of the Kingdom of God. After the Divine Liturgy we must continue to iconify the Kingdom of God, keeping His commandments. The glory of Christ is to bear fruit in every member His fruit. This explains His word: “Herein is my Father glorified, that ye bear much fruit” (John 15:8).

Source: I Knew A Man In Christ: The Life and Times of Elder Sophrony of Essex, the Hesychast and Theologian (Οίδα άνθρωπον εν Χριστώ: Βίος και πολιτεία του Γέροντος Σωφρονίου του ησυχαστού και θεολόγου) by Metropolitan Hierotheos of Nafpaktos and Agiou Vlasiou. Translated from Greek.

http://www.pantanassamonastery.org/before-the-new-testament-was-the-divine-liturgy.html
http://www.orthodoxpath.org/catechisms-and-articles/before-the-new-testament-was-the-divine-liturgy/