Our Father, who art in heaven, Hallowed be Thy Name; Thy kingdom come; Thy will be done on earth as it is in heaven; Give us this day our daily bread; And forgive us our trespasses, as we forgive those who trespass against us; And lead us not into temptation; But deliver us from evil. For Thine is the kingdom, and the power, and the glory, for ever and ever. Amen.
Why did the early Church introduce this prayer into the Communion Service [the second part: the Service of the Sacrament of the Altar]?
On account of its sacredness.
(a) From ancient times it has always been regarded as a divine and spiritual form of prayer, which can never fail to move our heavenly Father, because His Son taught us thus to pray. On this Cyprian says beautifully: “What prayer can be more spiritual than that which was given us by Christ, by Whom also the Holy Spirit was sent? What petition more true before the Father than that which came from the lips of His Son, Who is the Truth?”
(b) Its use was esteemed the peculiar privilege of true believers. Hence it was said, not in the first part of the worship [the Service of the Word], where we usually have it, but in the Communion Service, from which the heathen and catechumens (the unbaptized) were excluded. The latter were strictly forbidden to utter it. Chrysostom explains thus: “Not until we have been cleansed by the washing of the sacred waters are we able to call God, Father.”