St. Theodore the Studite ca. 759-826
You ask to be taught how you ought to pray. The Lord Himself taught us this through the invocation ‘Our Father’, and that we should not ask for anything temporary, but for His kingdom and eternal justice. Moreover it has been ordained by the Fathers that first should come thanksgiving to God; next confession of our sins to Him; and so a request for their forgiveness, and intercession for the other things that bring salvation.
So, when you are about to pray, give thanks to the Lord and Master that He brought you out of nothing into existence; that He redeemed you from every error, calling you and counting you worthy to become a partaker in the knowledge of Himself, free from pagan, free from heretical error. Next that He prepared you for the monastic life, which equals that of the Angels, after the enjoyment of life in the world. The thought of all this is enough to soften the soul to compunction and the outpouring of tears. From all this comes enlightenment of heart, sweetness of spirit, desire for God. When this is present inthe heart, there comes the rejection of every evil. When you have thus given thanks to God, confess to him like this, ‘You know, Master, how many sins I have committed against You, and how many I commit each hour, as You reckon up this sin and this offence and the ones committed in knowledge and inignorance. But do not recall in any detail the ones that by being clearly remembered harm the soul. [Cf. The Ladder 28:58] And from this the grace of humility will dawn for you, with a broken heart [Cf. Psalm 50:18] and fear of God’s recompense. After this, ask, groan, implore your Lord for forgiveness of these sins and strengthening for the future to please him, saying, ‘My Lord, Lord, may I no longer anger You, may I no longer love anything but You, alone truly to be loved. And should I anger you again, falling down I implore your compassion, that I may be given strength from now on to please you. ‘ And if anything else comes to your mind that is good to be accomplished, ask for it fervently. And after this call upon the holy Mother of God to have mercy on you, the holy Angels, and the Angel you have as the guardian of your life, that he may watch over you and protect you, the Forerunner and the holy Apostles, all the Saints and those whom you usually call on especially, and the one whose memory is kept that day. These then are the things, it seems to me, which hold the power of prayer, even if each person doubtless prays with other words and not the same as these, because people who pray do not always say the same things themselves, but the power, as I reckon, is always the same. So may you be kept safe as you pray for what is necessary, and become better each day, and through a strict way of life present your entire self well-pleasing to the Lord. (Letters Bk. 1.42 To the Nun Anna)