What follows is a selection of Psalms by St. Ephraim the Syrian. They can be found in the book A Spiritual Psalter, published by St. John of Kronstadt Press. This little book is very edifying and uplifting, and is highly recommended.
How to Relieve the Conscience of Inner Anxiety
O Lord and Master! O God of heaven and earth! Show Your favor and open to me the door of repentance, I pray You with my afflicted soul.
Regard me according to Your great mercy; incline Your ear to my prayer and forgive me, who am guilty of falling into many sins; forgive me all of the wretched things I have done, for I have been conquered by my own evil will.
I seek peace and do not find it, for my conscience is stained; there is no tranquility in me due to the multitude of my iniquities.
Hearken, O Lord, to a heart which cries out to You with affliction. Do not pay attention to my deeds, but to the affliction of my soul, and hasten to heal me who am cruelly wounded. Grant that I may soon come to my senses according to the grace of Your love for humanity.
Take from me the burden of my sins and grant me not that which my deeds merit, that I may not perish in the end, and that I may not be altogether deprived of thought and concern for my restoration.
I fall down before Your compassion; have mercy on me who am cast into the dust by the judgement of my deeds.
O Master, summon me, a captive who is held and bound by his deeds as with chains, for You alone know how to free those who are bound and how to heal the invisible sores that are known only to You Who know all mysteries.
Show Your favor and stretch out Your hand to me. Draw me out of the mire of my iniquities, O You Who does not rejoice at the destruction of man, and Who does not turn Your face from those who cry to You with tears.
Hearken, O Lord, unto the voice of Your servant, who cries to You; show Your face to me, for I am beclouded; enlighten me with the coming of Your Holy Spirit.
Grant me, O Lord, diligence, for I have become defiled, and turn my labor into joy.
Tear up my slackness and gird me with gladness; may the door of Your kingdom open to me that, having entered therein, I may glorify Your all-holy name of the Father, Son, and Holy Spirit.