Apostolic Constitutions, Book VII 24
1Now, when you pray, be not as the hypocrites; but as the Lord has appointed us in the Gospel, so pray: Our Father which art in heaven, hallowed be Your name; Your kingdom come; Your will be done, as in heaven, so on earth; give us this day our daily bread; and forgive us our debts, as we forgive our debtors; and lead us not into temptation, but deliver us from evil; for Yours is the kingdom forever. Amen. Pray thus thrice in a day, preparing yourselves beforehand, that you may be worthy of the adoption of the Father; lest, when you call Him Father unworthily, you be reproached by Him, as Israel once His first-born son was told: If I be a Father, where is my glory? And if I be a Lord, where is my fear? For the glory of fathers is the holiness of their children, and the honour of masters is the fear of their servants, as the contrary is dishonour and confusion. For says He: Through you my name is blasphemed among the Gentiles.