Феодор Мопсуестийский (А)Theodore of Mopsuestia, Commentary on the Lord's Prayer, Baptism and the Eucharist (1933) pp.1-123.
[Translated by Alphonse Mingana]
With your assistance, O Lord Jesus Christ, I will begin to write the explanation of the sacraments by the blessed Mar Theodore. Help me, our Lord, and bring my work to completion. Amen.
Chapter I.
Because by the grace of God we spoke to you yesterday of the subject of faith, which our blessed Fathers wrote for our instruction according to the words of the Divine Books, in order to initiate us, in accordance with the doctrine of our Lord, in the name of the Father and of the Son and of the Holy Spirit— it is fitting that we should speak to-day of the necessary things concerning the prayer which was taught by our Lord, and which they made to follow the words of the Creed, so that it should be learnt and kept in memory by those who come near to the faith of baptism. Our Lord also, after having said: "Go you, therefore, and teach all nations, baptising them in the name of the Father, and of the Son, and of the Holy Spirit," added: And teach them to observe all things I have commanded you." He showed in this that, alongside the doctrine of religion and the right knowledge, we should endeavour to harmonise our lives with the Divine commandments. They added to the words of the Creed the prayer which our Lord taught in short terms to His disciples, because it contains the teaching for good works, in a sufficient manner. Every prayer contains teaching of good works to any one who cares to think attentively of duty, because we wish our works to be that which we ask in our prayer that they should be. He who cares, therefore, for perfection and is anxious to do the things that are pleasing to God, will pay |2 more attention to prayer than any other thing, and he who does not care for any virtue and is not anxious to do the things that are pleasing to God, it is clear that he will show also no interest in prayer.