Most Holy Trinity, have mercy on us; Lord, cleanse our sins; Master, forgive our iniquities; Holy One, visit and heal our infirmities, for Thy name's sake.
Lord, cleanse our sins - an appeal to God the Father; Master, forgive our iniquities - Appeal to God the Son; Holy One, visit and heal our infirmities - an appeal to God the Holy Spirit; for Thy name's sake - for the glory of Thy name.
+ The first words of the prayer: Most Holy Trinity, have mercy on us - refer to all Three Persons of the Most Holy Trinity, to the One Being of God; then, to strengthen the prayer, a petition is raised to each Person separately: Lord... Master... Holy... Conclusion of the prayer: ... for Thy name's sake - again applies to all Persons, in order to confirm our faith in One God, Trinity in Persons: One Being of God, but in Three indivisible Persons.
The Being of God is incomprehensible to us. If the Angels do not comprehend the Trinity Being of God, but reverently worship and confess Him, then who are we to dare to test how this is One God in Three Persons? We cannot understand this with our minds; we can only accept with reverent faith what is incomprehensible and know what is open and known. It is revealed and known to us from the Word of God itself that there has been from time immemorial the One, Eternal God, that He is the Spirit, the All-Good, the All-Knowing, the All-Righteous, the Almighty, the Omnipresent, the Unchangeable, the All-Satisfied, the All-Blessed; that He is One in Essence, but Trinity in Persons: Father, Son and Holy Spirit, the Trinity Consubstantial and Indivisible. For three bear witness in heaven: the Father, the Word and the Holy Spirit; and these three are one (1 John 5:7).
“Just as man, divided into many things, is one by nature, so the Holy Trinity, although divided by names and hypostases, is one by nature. You cannot comprehend the nature of God, even if you soar to Him on wings. God is incomprehensible, like our Creator... Do not test the Trinity, but believe only and worship, for whoever tests does not believe.”
Venerable Neil of Sinai
(Philokalia vol. 2)
Lord, have mercy. (Thrice)
The Appendix provides St. Paisius Velichkovsky's interpretation of the prayer, Lord, have mercy.
+ “What is the meaning of the verb have mercy or be merciful in all these prayers? This is a person’s awareness of his destruction, this is a feeling of that mercy, that self-pity that the Lord commanded us to feel for ourselves and which is felt by very few; it is a denial of one's own dignity; this is a request for God’s mercy, without which there is no hope of salvation for the lost.”
Saint Ignatius Brianchaninov
“Whoever said: have mercy, made a confession and acknowledged his sins, because it is common for those who have sinned to desire mercy. Whoever said: have mercy on me received remission of sins, because he who has mercy is not punished. Whoever said: “Have mercy on me” has received the Kingdom of Heaven, because God, whoever has mercy, not only frees him from punishment, but also rewards him with future blessings.”
Saint John Chrysostom
Glory, and now:
Let us remind you once again that in all cases of such writings one should read in full: Glory to the Father, and to the Son, and to the Holy Spirit, now and ever, and unto ages of ages. Amen.