[…] What meaning do the verb phrases, have mercy, or be merciful contain in all these prayers?
It is man’s awareness that he is perishing;
it is the perception of the mercy and pity that the Lord commanded us to feel toward ourselves, but which very few actually do feel;
it is the rejection of our own self-opinion;
it is a request for God’s mercy, without which there is no hope of salvation for the one who is perishing.
God’s mercy is nothing other than the grace of the All-Holy Spirit, and we sinful ones should ceaselessly and unrelentingly ask it of God.
Have mercy, my Lord, upon the disastrous state into which I have fallen, having been deprived of Thy grace, and again make Thy grace to dwell in me.
Strengthen me with Thy governing spirit (Ps. 50:12), a spirit of Thy power, so that I might withstand the temptation brought against me by the devil, and the temptation that comes from my fallen nature.
Send me a spirit of chastity, so that I might come out of this state of delirium, and correct my moral steps.
Give me the Spirit of Thy fear, so that I might have [godly] fear of Thee, as it is proper for a weak creature to fear his great God and Creator, so that by my awe before Thee I might hold Thy commandments sacred.
Root love for Thee within my heart, so that I may never again be separated from Thee, nor be distracted by an irresistible attraction to loathsome sin.
Grant me Thy peace, that it might preserve my soul in unperturbed calm, not allowing my thoughts to wander over the entire universe without need and to my own injury, to my own confusion; that it might concentrate them in introspection, and bear them upwards thence to Thy throne.
Give me a Spirit of meekness, so that I might refrain from anger and malice, that I might be continually filled with goodness toward my brother.
Give me a Spirit of humility of mind, so that I would not be high-minded, or dream about myself, or seek praise and human glory; but that I might rather remember that I am earth and ashes, a fallen being, cast down to the earth for my unworthiness.
I must be taken from this body and world by death, and appear before Thy dread and impartial judgment.
God, be merciful to me a sinner! Lord Jesus Christ, Son of God, have mercy on me! Lord, have mercy!
Ignatius Brianchaninov (1807–1867; Russian Orthodox): Homily on the Sunday of the Publican and the Pharisee on Prayer and Repentance translated by Nun Cornelia Rees @ Pravoslavie.