This is a very short prayer rule from Saint Seraphim of Sarov (+1833), intended for use by those who are pressed by work or other secular burdens. It can be committed to memory fairly easily.
In Saint Seraphim's own words:
“Let any Christian, upon arising from sleep stand before the holy icons, and read:
The Lord’s Prayer “Our Father” thrice, in honor of the Most-holy Trinity;
Then the hymn to the Mother of God “O Virgin Mother of God, hail…” three times.
And finally, the Symbol of Our Faith once. Having completed this rule, let each one attend to the tasks to which he was appointed or to which he is called.
“During work at home or while traveling somewhere, let him quietly read ‘Lord Jesus Christ, Son of God, have mercy on me a sinner.’ If there are others in his vicinity while he is working, let him silently repeat ‘Lord have mercy…’ until supper.
“After supper, upon completing his tasks, let him quietly read ‘Most Holy Mother of God, save me a sinner,’ and let him repeat this until falling asleep.
“Going to bed, let any Christian again read the above-mentioned morning rule. Thereafter, let him go to sleep, having protected himself with the sign of the Cross.
“Keeping this rule, it is possible, to reach Christian perfection, for the three prayers indicated are the foundation of Christianity. The first, as the payer given [to us] by Christ Himself, is the model for all prayers. The second was brought from Heaven by the Archangel to greet the Virgin Mary, the Mother of Our Lord. The Creed contains in brief all of the salvific dogmas of the Christian Faith.”
To those who for whatever reason could not complete this little rule, Saint. Seraphim recommended reading it under whatever circumstance: during lessons, while walking, and even in bed. He based this advice on the words of the Scriptures “whosoever should call upon the name of the Lord shall be saved…”
St Seraphim’s rule for the morning and evening, was given in particular to those who are occupied with secular work during the day, and is therefore appropriate for use by Christians today.
Life of Saint Seraphim - from the Orthodox Church of America website.
